Question

Solve the equation.
4y^3 – 7y^2 + 28 = 16y

Answer 1

The roots are y=2, y=-2 and y=7/4

Explanation:

4y^3-7y^2+28=16y =0

subtract 16y from both sides

4y^3 -7y^2 - 16y +28 =0

Factor by Grouping

(4y^3 -7y^2) (-16y +28) =0

Greatest common factor

y^2(4y-7) -4(4y-7)

take y^2 and -4 as well as the repeated 4y-7

(4y-7) (-4+y^2)

change -4 to -2^2

(4y-7) (-2^2+y^2)

Similify

(4y-7). (y-2). (y+2)

y=7/4 y=2 y=-2

Credit to BlueGreen24

Answer 2

Answer: -2, 2, 7/4

***If the pictures is sideways, use the rotate button. I hope the explanation made sense!