Answer:
I believe it would be 21 units . dont let extra line's confuse you just pay attention to the letters its asking for
19.99 + 15= 34.99
40-34.99 = 12.51
Jenny received $5.01 change.
It's choice C as the root overhead bar goes over all of (x-7) and not just the x. So you have the correct answer.
f(x) = x^4+7
y = x^4+7
x = y^4+7
y^4 = x-7
y = FourthRoot(x-7)