solving Poly EQ by Factoring

[eb0nie]

Hello,

I think I have the concept but when I get to the end of the problem I cannot figure out what to do. I read my book and I think I missed something some where... Here is what I have so far.

2x³+3x²= 8x+12

- 8x+12 =-8x+12

2x³+3x²- 8x+12=0

2x²(x+1) 4(2x+3)

x-1=0 2x²-4 (2x+3)??? help please

Something in the last two line are wrong. The answer is {-2, -3/2, 2} I just can't figure out how to get there.

 

[Denis]

2x³+3x²= 8x+12
- 8x+12 =-8x+12 : should be -8x - 12
2x³+3x²- 8x+12=0

So correct equation is:
2x^3 + 3x^2 - 8x - 12 = 0

x^2(2x + 3) - 4(2x + 3) = 0 : kapish?

Finish it.

 

[eb0nie]

x^2(2x + 3) - 4(2x + 3) = 0

x^2-4= 0

x +/- ?4= +/-2

x= +/-2

_________________

2x+3=0

2x = -3

x= -3/2
___________

final answer is

{2, -2, -3/2}

Yayyy Thanks Denis!