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 $\color{blue}{ a = 4 }$ by the constant term $\color{blue}{c = -22} $.
$$ a \cdot c = -88 $$Step 3: Find out two numbers that multiply to $ a \cdot c = -88 $ and add to $ b = 3 $.
Step 4: All pairs of numbers with a product of $ -88 $ are:
| PRODUCT = -88 | |
| -1 88 | 1 -88 |
| -2 44 | 2 -44 |
| -4 22 | 4 -22 |
| -8 11 | 8 -11 |
Step 5: Find out which factor pair sums up to $\color{blue}{ b = 3 }$
| PRODUCT = -88 and SUM = 3 | |
| -1 88 | 1 -88 |
| -2 44 | 2 -44 |
| -4 22 | 4 -22 |
| -8 11 | 8 -11 |
Step 6: Replace middle term $ 3 x $ with $ 11x-8x $:
$$ 4x^{2}+3x-22 = 4x^{2}+11x-8x-22 $$Step 7: Apply factoring by grouping. Factor $ x $ out of the first two terms and $ -2 $ out of the last two terms.
$$ 4x^{2}+11x-8x-22 = x\left(4x+11\right) -2\left(4x+11\right) = \left(x-2\right) \left(4x+11\right) $$