Step 1 :
After factoring out $ 2 $ we have:
$$ 6x^{2}+14x+8 = 2 ( 3x^{2}+7x+4 ) $$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 = 7 $.
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 $\color{blue}{ b = 7 }$
PRODUCT = 12 and SUM = 7 | |
1 12 | -1 -12 |
2 6 | -2 -6 |
3 4 | -3 -4 |
Step 7: Replace middle term $ 7 x $ with $ 4x+3x $:
$$ 3x^{2}+7x+4 = 3x^{2}+4x+3x+4 $$Step 8: Apply factoring by grouping. Factor $ x $ out of the first two terms and $ 1 $ out of the last two terms.
$$ 3x^{2}+4x+3x+4 = x\left(3x+4\right) + 1\left(3x+4\right) = \left(x+1\right) \left(3x+4\right) $$