SOLUTION: 15x^2+8x-12=0

Question 1144532: 15x^2+8x-12=0
Answer by Edwin McCravy(20056) (Show Source): You can put this solution on YOUR website!

15x²+8x-12 = 0

Use the "AC" method:

Multiply 15 by 12, first and last numbers.

15×12 = 180

Look for two factors of 180 that differ by 8, the middle coefficient.

Doesn't take long to see that they are 18 and 10.

Give them signs necessary to form middle coefficient +8.

That is, +18-10 equals +8

So we write 15x²+8x-12 = 0 as

15x²+18x-10x-12 = 0

Factor the first two terms by taking out 3x

3x(5x+6)-10x-12 = 0

Factor the last two terms by taking out -2

3x(5x+6)-2(5x+6) = 0

Factor the whole left side by taking out (5x+6)

(5x+6)(3x-2) = 0

Set each factor = 0

5x+6=0;  3x-2=0
  5x=-6;   3x=2
   x=-6/5;  x=2/3

Edwin

RELATED QUESTIONS
15x^2+8x-12=0 solve tis by factorization (answered by Alan3354)

{{{8x-12=15x-4x}}} (answered by College Student)

Solve:... (answered by rothauserc)

8x-2=x^2+15x (answered by rothauserc)

solve -8x - 45 = 2 -... (answered by jim_thompson5910)

simplify:... (answered by Cromlix)

Factor completely. x^3 + 8x^2 + 15x (answered by checkley71)

15x^2+36x+12 (answered by richwmiller)

-15x^2+2+7x=0 (answered by checkley77)