12 = 7w i don't understand how this works

12/7 or 1.71428571429

Step-by-step explanation:

You have to isolate the variable to get the w by itself. It's right next to a 7 which also means 7 multiplied by w. We need to cancel out the seven to isolate the variable so to do this we divide by 7. We also need to do this to the other side of equation to keep it balanced.

-12 = 7w

/7      /7

-1.714...=w

(b) 240

step-by-step explanation:

first, we use the pythagorean formula using the given side lengths to find x. then we use x to find the side lengths. then we add the side lengths to find the perimeter.

pythagorean theorem formula:

a^2 + b^2 = c^2

(x - 20)^2 + (x - 40)^2 = x^2

x^2 - 40x + 400 + x^2 - 80x + 1600 = x^2

x^2 -120x + 2000 = 0

(x - 100)(x - 20) = 0

x - 100 = 0 or x - 20 = 0

x = 100 or x = 20

we see that the solution x = 20 must be discarded because it will give a negative side length and a side length of 0. the only valid solution is x = 100.

perimeter = sum of the lengths of the sides

perimeter = x + x - 20 + x - 40

perimeter = 3x - 60

replace x with 100.

perimeter = 3(100) - 60

perimeter = 300 - 60

perimeter = 240

r = 78539458390583095803458309458039485093485 or just 3

step-by-step explanation: