Brainliestttytttttdd

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Explanation:

I'll use the variable x in place of 'a'

The expression we need to factor is [tex]21x^2-57x+30[/tex] which is in the form [tex]ax^2+bx+c[/tex]

So,

We'll plug those three values into the quadratic formula

[tex]x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}\\\\x = \frac{-(-57)\pm\sqrt{(-57)^2-4(21)(30)}}{2(21)}\\\\x = \frac{57\pm\sqrt{729}}{42}\\\\x = \frac{57\pm27}{42}\\\\x = \frac{57+27}{42} \ \text{ or } \ x = \frac{57-27}{42}\\\\x = \frac{84}{42} \ \text{ or } \ x = \frac{30}{42}\\\\x = 2 \ \text{ or } \ x = \frac{5}{7}\\\\[/tex]

The two roots of [tex]21x^2-57x+30 =0[/tex] are [tex]x = 2 \text{ and } x = \frac{5}{7}[/tex]

The root x = 2 leads to the factor (x-2) after subtracting 2 from both sides.

The root [tex]x = \frac{5}{7}[/tex] leads to the factor (7x-5) after first multiplying both sides by 7, and then subtract 5 from both sides.

So we have this set of steps:

[tex]x = \frac{5}{7}\\\\7x = 5\\\\7x-5=0\\\\[/tex]

The two factors are (x-2) and (7x-5).

This leads to (x-2)(7x-5)

The last step is to replace x with 'a' so that the variables match up.

We arrive at  (a-2)(7a-5)

However, as the next section shows, we have a bit of a problem. Don't worry, it can be easily fixed.

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Let's expand out that factored expression we found earlier.

[tex](a-2)(7a-5)\\\\b(7a-5)\ \text{ ..... let b = a-2}\\\\7ab - 5b\\\\7a(b) - 5(b)\\\\7a(a-2) - 5(a-2)\ \text{ ..... plug in b = a-2}\\\\7a^2-14a - 5a+10\\\\7a^2-19a+10\\\\[/tex]

That's not good. We should have arrived at the original expression [tex]21a^2-57a+30[/tex]. To fix this discrepancy, we can stick a 3 out front and then notice that:

[tex]3(a-2)(7a-5) = 3(7a^2-19a+10) = 21a^2-57a+30[/tex]

The error has been fixed.

We have the full factorization of 3(a-2)(7a-5)

The order of the factors doesn't matter, so we could have written the answer as 3(7a-5)(a-2). Usually the factor without any variables will be listed first.

Based on the screenshot you posted, if that '7' is locked in place, then the only possible answer is 3(7a-5)(a-2) since you'll have 3 in the first slot, then a ( in the next slot. The other slots are filled out in a similar manner. There are no spaces between any symbol or letter.

The table is an illustration of a linear function

9. The student's rate

Take any two points from the table

[tex](x,y) =\{(1,644)\ (4,500)\}[/tex]

The rate is then calculated using:

[tex]Rate = \frac{y_2 -y_1}{x_2 -x_1}[/tex]

This gives

[tex]Rate = \frac{644 -500}{1-4}[/tex]

[tex]Rate = \frac{144}{-3}[/tex]

[tex]Rate = -48[/tex]

The statement that the student reads at a rate of 48 pages per hour is true

10. The pages in the novel

From the table, there are 644 pages left, after the student read for 1 hour.

This means that there are more than 644 pages in the novel.

The statement that the number of pages in the novel is 644 is false

11. The linear equation

This is calculated as:

[tex]y = Rate(x -x_1) + y_1[/tex]

So, we have:

[tex]y = -48(x -1) + 644[/tex]

[tex]y = -48x +48 + 644[/tex]

[tex]y = -48x +692[/tex]

The statement that the situation can be represented by the  equation y = -48x + 692 is true

Read more about linear equations at:

https://brainly.com/question/15602982

Answer:

Step-by-step explanation:

Answer:

13

Step-by-step explanation:

set equations equal to each other and solve for x

6x + 20 = -4x + 150

10x = 130

X = 13

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Explanation:

The smallest data value is 13. This is due to the stem 1 and leaf 3.

The largest is 47. This is from the stem 4 and leaf 7.

The span between these items is 47-13 = 34

Variables:

w= The\ year\ Civil\ War\ ended

The year the Greek city of Helike disappeared is -1/5(w)

sry if im wrong i hope this helps tho :)

Answer:

Hope this helps

Step-by-step explanation:

-1/5x=w

w=1865

so -1/5x=1865

x=-9325

Answer:

C

Step-by-step explanation:

y = 10

x = 8

The y intercept is 0 and the line runs through (0,0)

m = y / x This formula can only be used when the y incept is 0.

m = 10/8

m = 5/4

Equation

y = 5/4 x

3

Step-by-step explanation:

x = number of trucks with 16 tonnes capacity

y = number of trucks with 6 tonnes capacity

x + y = 11

16x + 6y = 126

the first equation gives us

x = -y + 11

and we use that in equation 2 :

16(-y + 11) + 6y = 126

-16y + 176 + 6y = 126

-10y = -50

10y = 50

y = 5

x = -y + 11 = -5 + 11 = 6

the number of 16 tonne trucks was 6.

Answer:

5.125 < 5.14 < 5.15 < 5 2/9

Step-by-step explanation:

i changed 103/20 to a decimal to make it easier and just left 5 2/9 the same, hope this helps <3

Answer:

Option D

Step-by-step explanation:

a^2 + b^2 = c^2

5^2+b^2=9^2

25+b^2=81

b^2=56

b=2√14

Answer:

-1

Step-by-step explanation:

(fg)(x) is the product of f(x) and g(x).

We can find (fg)(4) by first finding f(4) and g(4) and then multiplying the results together:

f(x) = 10 - 3x, so f(4) = 10 - 3(4) = -2, and

g(x) = x - 3/2, so g(4) = 4 - 3/2 = 1/2

Then (fg)(4) = (-2)(1/2) = -1

Answer: y = -(1/2)x - 1

Step-by-step explanation:

y=2x+3

This is written in the format of y = mx + b, where m is the slope and b the y-intercept.  The slope of this reference line is 2.  Perpendicular lines will have a slope that is the negative inverse of the slope of the reference line.  That means out new line will have a slope of -(1/2):

y = -(1/2)x + b

We can find b by entering the x and y for the given point (-4,1) and solve for b:

y = -(1/2)x + b

1 = -(1/2)(-4) + b

1 = 2 + b

b = -1

y = -(1/2)x - 1

This equation is perpendicular to y=2x+3 and goes through point (-4,1).  See attachment.

Answer:

y = -1/2x - 8

Step-by-step explanation:

You are looking for the equation in the form of y=mx + b, so you need y on the left hand side without x. Subtract x from both sides.

2y = -x - 16

Now you want 1y instead of 2y. So divide everything by 2.

y = -1/2x - 8

Answer:

I would say not valid

Step-by-step explanation:

well, it would actually be 44% since 33/75= 0.44 to represent the number of ppl hat consider math their favorite subject

Answer:

23 starfish, 7 octopi

Step-by-step explanation:

x=starfish

y=octopi

x+y=30

5x+8y=171

-5(x+y=30)

5x+8y=171

-5x-5y=-150

5x+8y=171

3y= 21

y=7

x+7=30

x=23

23 starfish, 7 octopi

Answer:

x = 36

Here's how I got that:

   - Group like terms -

x - 2 + 2x + 4 + 2x - 2 = 180

                    ↓

      5x - 2 + 4 - 2 = 180

                    ↓

              5x = 180

 - Divide both sides by 5 -

         5x/5 = 180/5

                   ↓

               x = 36

~ That's all folks ~

-Siascon

Answer:

-6x -6= 10

Step-by-step explanation:

-2(x +3) -4x= 10

Expand:

-2(x) -2(3) -4x= 10

-2x -6 -4x= 10

Simplify:

-6x -6= 10

Thus, the second option is correct.

Answer:

x=-10,8

length=13

width=5

Step-by-step explanation:

(x+5)(x-3)=65

x^2+2x-15-65=0

x^2+2x-80=0

(x+10)(x-8)=0

x=-10,8

x+5

(-10)+5=-5, negative length does not make sense

x+5

8+5=13

x-3

(-10)-3=-13, negative width does not make sense

x-3

(8)-3=5

Answer:

x=8

length= 13inches

width=5inches

Step by step explanation:

A=lw

65= (x+5)(x-3)

65= x²-3x+5x-15

x²+2x-80=0

x²+ 10x - 8x - 80 = 0

x(x+10) -8(x+10) = 0

(x-8)(x+10)=0

x= 8 or -10

x cannot be negative

hence x= 8

length= x+5

=8+5

=13inches

width= x-3

=8-3

=5inches

The number of races the team need to win today for the team to have a 75% success rate is 15

Number of attempt = 45

Number of winnings = 30

Percentage won so far = 30/45 × 100

= 66.67%

let

x = Number of races that tfe team needs to win to have 75% success rate

(30 + x) / (45 + x) = 0.75

Cross product

30 + x = 0.75(45 + x)

30 + x = 33.75 + 0.75x

x - 0.75x = 33.75 - 30

0.25x = 3.75

x = 3.75 / 0.25

x = 15

Therefore, the number of races the team need to win today for the team to have a 75% success rate is 15

Learn more about percentage:

https://brainly.com/question/7225231

Answer:

  3000 +219d

Step-by-step explanation:

The food booth rental revenue is ...

  11(100 +9d) = 1100 +99d

The game booth rental revenue is ...

  20(95 +6d) = 1900 +120d

Then the total revenue is ...

  (1100 +99d) +(1900 +120d) = 3000 +219d

Answer:

Step-by-step explanation:

Given:

The change in temperature is:

Answer:

dude I would love to help but I don't speak taco bell I'm sorry :/

Answer:

Step-by-step explanation:

BOX #1 -- 2x

BOX #2 -- 4x

BOX #3 -- 8

BOX #4 -- 16

BOX #5 -- 4

Answer:

9 miles per hour

Step-by-step explanation:

He goes 3/4 of a mile in 15 minutes, so multiply x 4 to get how far per hour. 3/4 x 4 = 12/4 = 3 miles per hour. He went for 3 hours, so 3 x 3 = 9.

Answer:

The answer is 3240

hope it helps

can I get branliest

Answer:

Option A: [tex]x=0[/tex], [tex]x=-2[/tex], and [tex]x=-4[/tex]

Step-by-step explanation:

[tex]f(x)=x^3+6x^2+8x[/tex]

[tex]0=x^3+6x^2+8x[/tex]

[tex]0=x(x^2+6x+8)[/tex]

[tex]0=x(x+2)(x+4)[/tex]

[tex]x=0[/tex], [tex]x=-2[/tex], and [tex]x=-4[/tex]

[tex]x^3+6x^2+8x = 0\\\\\implies x^3+2x^2 +4x^2+8x =0\\\\\implies x^2(x+2) +4x (x+2) =0\\\\\implies (x+2)(x^2 +4x) = 0\\\\\implies x (x+2) (x+4)=0\\\\\text{Hence,} \\\\x = 0 ,-2,-4[/tex]

Answer:

1 I don't know if those are questions but try if they are try the first one a

Answer:

These are the answers

Step-by-step explanation:

The orbit of a planet is an ellipse, with the Sun at one of the two foci.

A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.

The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.

Hope it helped !

Answer:

The universal law of gravitation states that every particle attracts every other particle in the universe with a force that is directly proportional to the ...

Bernoulli formula: define focal length

Si unit of thrust: newton's third law of motion examples

12/15 ounces

this is because 8/15 + 4/15 = 12/15

hope this is helpful!