Question

Which function has two x-intercepts, one at (0, 0) and one at (4, 0)?

f(x) = x(x − 4)
f(x) = x(x + 4)
f(x) = (x − 4)(x − 4)
f(x) = (x + 4)(x + 4)

Answer 1

f(x) = x(x − 4)

Because f(x)=x(x−4)=0 when x=0 or x=4. The others have roots at x=−4 (second and fourth) or a repeated root at x=4 only (third).