Question

The x-intercepts and vertex

Answer 1

( - 6, 0).(2, 0 ) , vertex = ( - 2, - 16)

to find the x-intercepts set f(x) = 0

x² + 4x - 12 = 0

(x + 6)(x - 2) = 0 ( equate each factor to zero and solve for x )

x + 6 = 0 ⇒ x = - 6

x - 2 = 0 ⇒ x = 2

x- intercepts are ( - 6, 0),(2, 0)

given the quadratic in standard form : y = ax² + bx + c

the x-coordinate of the vertex = - $\frac{b}{2a}$

here a = 1 , b = 4 and c = - 12

x- coordinate of vertex = - $\frac{4}{2}$ = - 2

substitute this value into the equation for y-coordinate

x = - 2 → y = 4 - 8 - 12 = - 16

vertex = ( - 2, - 16)