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