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 = -2} $.
$$ a \cdot c = -28 $$Step 3: Find out two numbers that multiply to $ a \cdot c = -28 $ and add to $ b = 27 $.
Step 4: All pairs of numbers with a product of $ -28 $ are:
PRODUCT = -28 | |
-1 28 | 1 -28 |
-2 14 | 2 -14 |
-4 7 | 4 -7 |
Step 5: Find out which factor pair sums up to $\color{blue}{ b = 27 }$
PRODUCT = -28 and SUM = 27 | |
-1 28 | 1 -28 |
-2 14 | 2 -14 |
-4 7 | 4 -7 |
Step 6: Replace middle term $ 27 x $ with $ 28x-x $:
$$ 14x^{2}+27x-2 = 14x^{2}+28x-x-2 $$Step 7: Apply factoring by grouping. Factor $ 14x $ out of the first two terms and $ -1 $ out of the last two terms.
$$ 14x^{2}+28x-x-2 = 14x\left(x+2\right) -1\left(x+2\right) = \left(14x-1\right) \left(x+2\right) $$