Help pls.

13 hours

Step-by-step explanation:

The scenario that is being described can be fully made into an equation using three variables. These would be w for the number of weeks, b for the number of hours she babysat that week, and x for the total amount of hours worked. Like so...

5w + t = x

Since we are told that we need to find the total hours worked for a single week (w = 1) and that Erica babysat for 8 hours that week (b = 8), then we only need to solve for the total amount of hours worked (x)

5(1) + 8 = x

5+8 = x

13 = x

Erica worked a total of 13 hours.

Asked and answered here--->  

(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