Jessica is selling books during the summer to earn money for college. She earns a commission on each sale but has to
pay for her own expenses.
After a month of driving from neighborhood to neighborhood and walking
door-to-door, she figures out that her weekly earnings are approximately a
linear function of the number of doors she knocks on.
She writes the equation of the function like this: E(x) = 10x - 30, where xis the
number of doors she knocks on during the week and E(x) is her earnings for
the week in dollars.
Which of the following
are
Jessica's function?
reasonable interpretations of the y-intercept of
Check all that apply.

sites:

(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

nope.   happens to me as well.

-aparri