Step 1 :
After factoring out $ -5n $ we have:
$$ -10n^{3}+35n^{2}-45n = -5n ( 2n^{2}-7n+9 ) $$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 $\color{blue}{ a = 2 }$ by the constant term $\color{blue}{c = 9} $.
$$ a \cdot c = 18 $$Step 4: Find out two numbers that multiply to $ a \cdot c = 18 $ and add to $ b = -7 $.
Step 5: All pairs of numbers with a product of $ 18 $ are:
PRODUCT = 18 | |
1 18 | -1 -18 |
2 9 | -2 -9 |
3 6 | -3 -6 |
Step 6: Find out which factor pair sums up to $\color{blue}{ b = -7 }$
Step 7: Because none of these pairs will give us a sum of $ \color{blue}{ -7 }$, we conclude the polynomial cannot be factored.