The answer is y = 2x3 + 4x2 – x + 5 and y = –3x2 + 4x + 9
Roots are both: x=-4, x= -1/2 , x= 1
Proof:
Solve for x over the real numbers:
2 x^3 + 4 x^2 - x + 5 = -3 x^2 + 4 x + 9
Subtract -3 x^2 + 4 x + 9 from both sides:
2 x^3 + 7 x^2 - 5 x - 4 = 0
The left hand side factors into a product with three terms:
(x - 1) (x + 4) (2 x + 1) = 0
Split into three equations:
x - 1 = 0 or x + 4 = 0 or 2 x + 1 = 0
Add 1 to both sides:
x = 1 or x + 4 = 0 or 2 x + 1 = 0
Subtract 4 from both sides:
x = 1 or x = -4 or 2 x + 1 = 0
Subtract 1 from both sides:
x = 1 or x = -4 or 2 x = -1
Divide both sides by 2:
Answer: x = 1 or x = -4 or x = -1/2