Question

Sanjay graphs a quadratic function that has x-intercepts of -3 and 7. Which functions could he have graphed? Check all that apply.

a) (9x = 12)
b) (4x - 21)
c) (9x = (x - 3)(x + 7))
d) (9x = 312 - 12x - 63)
e) (9x = -(x + 3)(x - 7))
f) (g(x) = 12 + 4x - 21)

Answer 1

Sanjay could have graphed the quadratic functions f(x) = 9(x - 3)(x + 7) or f(x) = 9(x + 3)(x - 7).

Step-by-step explanation:

The quadratic function that has x-intercepts of -3 and 7 can be written in the form f(x) = a(x - r)(x - s), where r and s are the x-intercepts. In this case, r = -3 and s = 7. So the possible functions that Sanjay could have graphed are:

• (c) f(x) = 9(x - 3)(x + 7)
• (e) f(x) = 9(x + 3)(x - 7)

The other options are not quadratic functions and do not have the correct x-intercepts.