Can someone help confirm my work? f(x) = 4x2 − 7x − 15 Part A Finding X-intercepts: f(x) = 4x^2 − 7x − 15 0 = 4x^2 − 7x − 15 a = 4, b = -7, c= -15 a * c = -60 -12 * 5 = -60 -12 + 5 = -7 (4

Can someone help confirm my work?

f(x) = 4x2 − 7x − 15

Part A Finding X-intercepts:

f(x) = 4x^2 − 7x − 15

0 = 4x^2 − 7x − 15

a = 4, b = -7, c= -15

a * c = -60

-12 * 5 = -60

-12 + 5 = -7

(4x + 5)(4x -12)

4x^2 - 12x | + 5x -15

4x(x - 3) + 5(x - 3)

(x - 3)(4x +5)

x = 3 x = -1.25 or -5/4

Part B Finding Vertex:

minimum point

(x1 + x2)/2

(3 -1.25)/2 = 0.875

f(x) = 4x^2 − 7x − 15

f(0.875) = 4(0.875)^2 − 7(0.875) − 15

f(0.875) = 3.06 - 6.125 - 15

f(0.875) = -18.065

vertex = (0.875, -18.065)