Step 1 :
After factoring out $ 3 $ we have:
$$ 9x^{2}+24x-12 = 3 ( 3x^{2}+8x-4 ) $$Step 2 :
Step 2: Identify constants $ a $ , $ b $ and $ c $.
$ a $ is a number in front of the $ x^2 $ term $ b $ is a number in front of the $ x $ term and $ c $ is a constant. In this case:
Step 3: Multiply the leading coefficient $\color{blue}{ a = 3 }$ by the constant term $\color{blue}{c = -4} $.
$$ a \cdot c = -12 $$Step 4: Find out two numbers that multiply to $ a \cdot c = -12 $ and add to $ b = 8 $.
Step 5: All pairs of numbers with a product of $ -12 $ are:
PRODUCT = -12 | |
-1 12 | 1 -12 |
-2 6 | 2 -6 |
-3 4 | 3 -4 |
Step 6: Find out which factor pair sums up to $\color{blue}{ b = 8 }$
Step 7: Because none of these pairs will give us a sum of $ \color{blue}{ 8 }$, we conclude the polynomial cannot be factored.