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 $\color{blue}{ a = 14 }$ by the constant term $\color{blue}{c = 8} $.
$$ a \cdot c = 112 $$Step 3: Find out two numbers that multiply to $ a \cdot c = 112 $ and add to $ b = -23 $.
Step 4: All pairs of numbers with a product of $ 112 $ are:
PRODUCT = 112 | |
1 112 | -1 -112 |
2 56 | -2 -56 |
4 28 | -4 -28 |
7 16 | -7 -16 |
8 14 | -8 -14 |
Step 5: Find out which factor pair sums up to $\color{blue}{ b = -23 }$
PRODUCT = 112 and SUM = -23 | |
1 112 | -1 -112 |
2 56 | -2 -56 |
4 28 | -4 -28 |
7 16 | -7 -16 |
8 14 | -8 -14 |
Step 6: Replace middle term $ -23 x $ with $ -7x-16x $:
$$ 14x^{2}-23x+8 = 14x^{2}-7x-16x+8 $$Step 7: Apply factoring by grouping. Factor $ 7x $ out of the first two terms and $ -8 $ out of the last two terms.
$$ 14x^{2}-7x-16x+8 = 7x\left(2x-1\right) -8\left(2x-1\right) = \left(7x-8\right) \left(2x-1\right) $$