Step 1 :
After factoring out $ 9 $ we have:
$$ 18j^{2}+9j-27 = 9 ( 2j^{2}+j-3 ) $$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 $\color{blue}{ a = 2 }$ by the constant term $\color{blue}{c = -3} $.
$$ a \cdot c = -6 $$Step 4: Find out two numbers that multiply to $ a \cdot c = -6 $ and add to $ b = 1 $.
Step 5: All pairs of numbers with a product of $ -6 $ are:
PRODUCT = -6 | |
-1 6 | 1 -6 |
-2 3 | 2 -3 |
Step 6: Find out which factor pair sums up to $\color{blue}{ b = 1 }$
PRODUCT = -6 and SUM = 1 | |
-1 6 | 1 -6 |
-2 3 | 2 -3 |
Step 7: Replace middle term $ 1 x $ with $ 3x-2x $:
$$ 2x^{2}+x-3 = 2x^{2}+3x-2x-3 $$Step 8: Apply factoring by grouping. Factor $ x $ out of the first two terms and $ -1 $ out of the last two terms.
$$ 2x^{2}+3x-2x-3 = x\left(2x+3\right) -1\left(2x+3\right) = \left(x-1\right) \left(2x+3\right) $$