Question

Which equation, when graphed, has x-intercepts at (8, 0) and (−2, 0) and a y-intercept at (0, −48)?

f(x) = −3(x − 8)(x + 2)
f(x) = −3(x + 8)(x − 2)
f(x) = 3(x − 8)(x + 2)
f(x) = 3(x + 8)(x − 2)

Answer 1

f(x) = 3(x − 8)(x + 2)

Reason: with zeros at 8 and −2 the form is f(x)=a(x−8)(x+2). f(0)=−16a must equal −48, so a=3.