The answer is (f * g) (x) = 12x
80 inches, diameter is twice radius
B because all of the other ones are correct-
Step-by-step explanation:
well,
(y - 7)² = (y - 7)(y - 7)
remember how to multiply 2 expressions ?
you have to multiply every term of one expression with every term of the other expression and sum the results all up (incl. considering their individual signs, of course).
so, when we do the multiplication, we get
(y - 7)(y - 7) = y×y - 7×y - 7×y + (-7)×(-7) =
= y² - 14y + 49
and that is clearly different to y² - 49
FYI
y² - 49 is the result of
(y - 7)(y + 7)
because
y×y + 7×y - 7×y + (-7)(7) = y² - 49
