Question

R is the midpoint of AM. If RA = x2 - 16x and MR = 80, find x.

Answer 1

x = - 4 or x = 20

Explanation:

Given R is the midpoint of AM, then

RA = MR , substitute values

x² - 16x = 80 ( subtract 80 from both sides )

x² - 16x - 80 = 0 ← in standard form

(x - 20)(x + 4) = 0 ← in factored form

Equate each factor to zero and solve for x

x - 20 = 0 ⇒ x = 20

x + 4 = 0 ⇒ x = - 4