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 $\color{blue}{ a = 5 }$ by the constant term $\color{blue}{c = 35} $.
$$ a \cdot c = 175 $$Step 3: Find out two numbers that multiply to $ a \cdot c = 175 $ and add to $ b = -32 $.
Step 4: All pairs of numbers with a product of $ 175 $ are:
PRODUCT = 175 | |
1 175 | -1 -175 |
5 35 | -5 -35 |
7 25 | -7 -25 |
Step 5: Find out which factor pair sums up to $\color{blue}{ b = -32 }$
PRODUCT = 175 and SUM = -32 | |
1 175 | -1 -175 |
5 35 | -5 -35 |
7 25 | -7 -25 |
Step 6: Replace middle term $ -32 x $ with $ -7x-25x $:
$$ 5x^{2}-32x+35 = 5x^{2}-7x-25x+35 $$Step 7: Apply factoring by grouping. Factor $ x $ out of the first two terms and $ -5 $ out of the last two terms.
$$ 5x^{2}-7x-25x+35 = x\left(5x-7\right) -5\left(5x-7\right) = \left(x-5\right) \left(5x-7\right) $$