Step 1 :
After factoring out $ -1 $ we have:
$$ -5x^{2}-27x-10 = - ~ ( 5x^{2}+27x+10 ) $$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 $\color{blue}{ a = 5 }$ by the constant term $\color{blue}{c = 10} $.
$$ a \cdot c = 50 $$Step 4: Find out two numbers that multiply to $ a \cdot c = 50 $ and add to $ b = 27 $.
Step 5: All pairs of numbers with a product of $ 50 $ are:
| PRODUCT = 50 | |
| 1 50 | -1 -50 |
| 2 25 | -2 -25 |
| 5 10 | -5 -10 |
Step 6: Find out which factor pair sums up to $\color{blue}{ b = 27 }$
| PRODUCT = 50 and SUM = 27 | |
| 1 50 | -1 -50 |
| 2 25 | -2 -25 |
| 5 10 | -5 -10 |
Step 7: Replace middle term $ 27 x $ with $ 25x+2x $:
$$ 5x^{2}+27x+10 = 5x^{2}+25x+2x+10 $$Step 8: Apply factoring by grouping. Factor $ 5x $ out of the first two terms and $ 2 $ out of the last two terms.
$$ 5x^{2}+25x+2x+10 = 5x\left(x+5\right) + 2\left(x+5\right) = \left(5x+2\right) \left(x+5\right) $$