Answer:
f(x) = -3(x+3)(x-1)
Step-by-step explanation:
x = -3 & 1; f(x) = 9
f(x) = a(x-r1)(x-r2)
f(0) = a(x-r1)(x-r2) = 9; 9 = a(0-(-3))(0-1)
9 = a(3)(-1); 9 = a(-3)
a = -3
f(x) = -3(x+3)(x-1)
Answer:
f(x) = -3x^2 - 6x + 9.
Step-by-step explanation:
As the x intercepts are - 3 and 1 we can write it as:
f(x) = a(x - 1)(x + 3) where a is a constant to be found.
As the - intercept is at (0, 9), x =0 when f(x) = 9 so we can also write:
a( 0 - 1)(0 + 3) = 9
(-1)(3)a = 9
a = 9 / -3
= -3.
So the equation is f(x) = -3(x - 1)(x + 3)
In expanded form it is
-3(x^2 + 2x - 3)
= -3x^2 - 6x + 9.
