It seems that $ 10y^{2}+7y+9 $ cannot be factored out.
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 = 9} $.
$$ a \cdot c = 90 $$Step 3: Find out two numbers that multiply to $ a \cdot c = 90 $ and add to $ b = 7 $.
Step 4: All pairs of numbers with a product of $ 90 $ are:
PRODUCT = 90 | |
1 90 | -1 -90 |
2 45 | -2 -45 |
3 30 | -3 -30 |
5 18 | -5 -18 |
6 15 | -6 -15 |
9 10 | -9 -10 |
Step 5: Find out which factor pair sums up to $\color{blue}{ b = 7 }$
Step 6: Because none of these pairs will give us a sum of $ \color{blue}{ 7 }$, we conclude the polynomial cannot be factored.