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 $\color{blue}{ a = 10 }$ by the constant term $\color{blue}{c = 10} $.
$$ a \cdot c = 100 $$Step 3: Find out two numbers that multiply to $ a \cdot c = 100 $ and add to $ b = -29 $.
Step 4: All pairs of numbers with a product of $ 100 $ are:
PRODUCT = 100 | |
1 100 | -1 -100 |
2 50 | -2 -50 |
4 25 | -4 -25 |
5 20 | -5 -20 |
10 10 | -10 -10 |
Step 5: Find out which factor pair sums up to $\color{blue}{ b = -29 }$
PRODUCT = 100 and SUM = -29 | |
1 100 | -1 -100 |
2 50 | -2 -50 |
4 25 | -4 -25 |
5 20 | -5 -20 |
10 10 | -10 -10 |
Step 6: Replace middle term $ -29 x $ with $ -4x-25x $:
$$ 10x^{2}-29x+10 = 10x^{2}-4x-25x+10 $$Step 7: Apply factoring by grouping. Factor $ 2x $ out of the first two terms and $ -5 $ out of the last two terms.
$$ 10x^{2}-4x-25x+10 = 2x\left(5x-2\right) -5\left(5x-2\right) = \left(2x-5\right) \left(5x-2\right) $$