Mary is doing research on bird migration. Last week she counted 12 migration birds in her yard. This week she counted 10. What was the percent decrease in birds this week?​

Answer:

[tex]\frac{1}{4}[/tex]

Step-by-step explanation:

The problem [tex]2x - 3x = 3[/tex] is incorrect. The correct answer for that one is [tex]-x \:\sf{or\:-1[/tex]

[tex]\sf{Simplify\: the\: expression.[/tex]

[tex]\sf{\frac{16x}{64x} = \frac{1}{4}[/tex]

[tex]x=\frac{1}{4}[/tex]

Therefore, the answer is [tex]\frac{1}{4}[/tex]

Answer:

Step-by-step explanation:

1

Answer:

A. 20

Step-by-step explanation:

1. To solve this problem, instead of doing 80/100 times 16, we can do 100/80 times 16 (inverse of percentage, basically).

Therefore, the answer is A. 20.

Answer:

625.25

Step-by-step explanation:

the answer is 625.25

Answer: 625.25

Step-by-step explanation:

Based on the information given the percent of the total cost of the bike has Wu saved is 30%.

Using this formula

Total cost percentage=Amount saved/Cost×100

Where:

Amount saved=$75

Cost =$250

Let plug in the formula

Total cost percentage=$75/$250×100

Total cost percentage=30%

Inconclusion the percent of the total cost of the bike has Wu saved is 30%.

Learn more here:

https://brainly.com/question/17157877

Answer:

9/2

Step-by-step explanation:

m=∆y/∆x

m= (5+4)/(2—0)

m=9/2

Answer:

3:4 itself.

3:4 itself.

Step-by-step explanation:

3:4 itself.

9514 1404 393

Answer:

  (c) 5y - x = -20

Step-by-step explanation:

When the x- and y-terms are on the same side of the equation, the slope of the line will be ...

  m = -(coefficient of x)/(coefficient of y)

So, the slopes of the offered choices are ...

  a) -5/1 = -5

  b) -1/5

 c) -(-1)/5 = 1/5 . . . . . parallel to given line

  d) -5/-1 = 5

The lines will be parallel when their slopes are the same. The slope of the given line is the coefficient of x, 1/5. Choice C has the same slope.

Answer:

i think it is :

5×5×5=125

2×2×2=8

Answer:

10.4

Step-by-step explanation:

x=3⇒f(3)= 4×3+3=15

x=3⇒g(3)=8/3+2≈4.6

f(3)-g(3)=15-4.6=10.4

Step-by-step explanation:

sorry for my bad handwriting, hope it helps

-2 1/2 - (-1 3/4)

When subtracting a negative vile the equation becomes addition:

-2 1/2 + 1 3/4 = -3/4

Answer: -3/4

Answer:479001600

Step-by-step explanation:

12 factorial is 12 * 11 * 10 ..... all the way to one

A way to do it by hand is

12 * 1

11 * 2

10 * 3

9 * 4

8 * 5

7 * 6

stop here because 6 * 7 and 5 *8 are already listed

This gives you 6 products then multiply those 6 products by pairs which gives you three pairs which gives you three products then compute a pair then multiply by last product.

Easy math but a lot of written work

Answer:

$20

Step-by-step explanation:

correct me if im wrong(┬┬﹏┬┬)

[tex] \: \: \: \: \: \: [/tex]

[tex] = 3a ^{4} \times (7 {a}^{5} - 2)[/tex]

Step-by-step explanation:

[tex]21 {a}^{9} - 6 {a}^{4} [/tex]

[tex] = 3 {a}^{4} \times (7 {a}^{5} - 2)[/tex]

[tex] \: \: \: \: \: \: [/tex]

a. By the chain rule,

[tex]\dfrac{dy}{dx} = \dfrac{dy}{dt}\cdot\dfrac{dt}{dx} = \dfrac{dy}{dt}\cdot\dfrac{1}{\frac{dx}{dt}}[/tex]

Given that [tex]y=e^t+e^{-t}[/tex] and [tex]x=e^{-t}[/tex], we have the derivatives

[tex]\dfrac{dy}{dt} = e^t -e^{-t}[/tex]

[tex]\dfrac{dx}{dt} = -e^{-t}[/tex]

and so

[tex]\dfrac{dy}{dx} = \dfrac{e^t - e^{-t}}{-e^{-t}} = 1-e^{2t}[/tex]

Set this equal to zero and solve for t :

[tex]1-e^{2t} = 0[/tex]

[tex]1 = e^{2t}[/tex]

[tex]\ln(1) = \ln\left(e^{2t}\right)[/tex]

[tex]0 = 2t \ln(e)[/tex]

[tex]0 = 2t[/tex]

[tex]t=0[/tex]

This value of t corresponds to x = e⁰ = 1 and y = e⁰ - 1/e⁰ = 1 - 1 = 0. So the only point on the curve where the derivative dy/dx is zero is (1, 0).

b. Compute the second derivative. Since dy/dx is a function of t, we'll momentarily replace it with f(t). By the chain rule,

[tex]\dfrac{d^2}{dx^2} = \dfrac d{dx} \dfrac{dy}{dx} = \dfrac{df}{dx} = \dfrac{df}{dt}\cdot\dfrac{dt}{dx} = \dfrac{df}{dt}\cdot\dfrac{1}{\frac{dx}{dt}}[/tex]

We have

[tex]\dfrac{df}{dt} = -2e^{2t}[/tex]

and we've already committed dx/dt. So

[tex]\dfrac{d^2}{dx^2} = \dfrac{-2e^{2t}}{-e^{-t}} = 2e^{3t} [/tex]

Substitute the first and second derivative into the differential equation:

[tex]\left(\dfrac{d^2y}{dx^2}\right)^2 + \dfrac{dy}{dx} - 1 = 0[/tex]

[tex]\left(2e^{3t}\right)^2 + (1-e^{2t}) - 1 = 0[/tex]

[tex]4e^{6t} -e^{2t}= 0[/tex]

[tex]e^{2t} (4e^{4t} - 1) = 0[/tex]

[tex]4e^{4t} - 1 = 0[/tex]

[tex]4e^{4t} = 1[/tex]

[tex]e^{4t} = \dfrac14[/tex]

[tex]\ln\left(e^{4t}\right) = \ln\left( \dfrac14\right)[/tex]

[tex]4t \ln(e) = -\ln(4)[/tex]

[tex]4t = -\ln(4)[/tex]

[tex]t = -\dfrac{\ln(4)}4[/tex]

Answer:

.923

Step-by-step explanation:

1.3 X 0.71 = .923

:))

Answer:

yes...

Step-by-step explanation:

k

Answer:

y = 5 x + 7

Step-by-step explanation:

Answer: Yes

Step-by-step explanation: They are similar because it the same kind of triangle just ones smaller and the other is bigger.

Answer:

[tex]-\frac{x(15x^4-2x^3+3)}{3}[/tex]

Step-by-step explanation:

[tex]\frac{30x^8-4x^7+6x^4}{-6x^3}[/tex]

The first thing I would do is to factor the numerator. All coefficients there are divisible by 2, and all variables are divisible by x⁴. I'll also move the negative sign to the left.

[tex]-\frac{2x^4(15x^4-2x^3+3)}{6x^3}[/tex]

Next, you can simplify 2/6 to 1/3:

[tex]-\frac{x^4(15x^4-2x^3+3)}{3x^3}[/tex]

Finally, the last thing you can do is simplify x⁴/x³ to x/0:

[tex]-\frac{x(15x^4-2x^3+3)}{3}[/tex]

That's as simplified as it gets.

9514 1404 393

Answer:

  (c)  ΔTRS

Step-by-step explanation:

Perhaps the easiest way to find corresponding vertices is to look at the angle markings:

  1 mark: angles J and T

  2 marks: angles K and R

  3 marks: angles I and S

Then, in order of corresponding angles, we have ...

  ΔJKI ≅ ΔTRS

Answer:

(1, -4)

Step-by-step explanation:

(-5,-4) -> (x,y) so x = -5 and y = -4. Apply the rule (x+6,y) to that point by substituting in your x and y values.

(-5+6,-4) = (1, -4)

Answer:

Neither.

Step-by-step explanation:

Manipulate the formulas into slope-intercept form which is [tex]y=mx+b[/tex].

In order for them to be parallel, m needs to be the same. Perpendicular, m for one needs to be the negative reciprocal of the other [tex]m=-\frac{1}{m}[/tex].

Let's see what we get.

(1)

[tex]3x+4y=2\\4y=-3x+2\\y=-\frac{3}{4}x+1/2[/tex]

(2)

[tex]4x+3y=2\\3y=-4x+2\\y=-\frac{4}{3}x+2/3[/tex]

They are reciprocals, but they are both negative. So, they are not the same line, perpendicular, nor parallel.

Also, you can graph these equations on desmos and see easily that they have none of these relationships.

Answer:

-3 - (2w)

Step-by-step explanation:

hope this helps!