Question

1, Find the x-intercept/s and y-intercept of the polynomial equation below: Y=2x³+4x²-2x-4.

Answer 1

x-intercept ⇒ y = 0

2x³+4x²-2x-4 = 0 : 2

x³+2x²-x-2 = 0

(x³+2x²)-(x+2) = 0

x²(x+2)-(x+2)=0

(x+2)(x²-1)=0

(x+2)(x²-1²)=0

(x+2)(x+1)(x-1)=0

x = -2, x = -1, x = 1

(-2,0) , (-1,0), (1,0)

y-intercept ⇒ x = 0

Y=2(0)³+4(0)²-2(0)-4

Y=-4

(0,-4)