Step 1 :
After factoring out $ x $ we have:
$$ 7x^{3}+24x^{2}+18x = x ( 7x^{2}+24x+18 ) $$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 $\color{blue}{ a = 7 }$ by the constant term $\color{blue}{c = 18} $.
$$ a \cdot c = 126 $$Step 4: Find out two numbers that multiply to $ a \cdot c = 126 $ and add to $ b = 24 $.
Step 5: All pairs of numbers with a product of $ 126 $ are:
PRODUCT = 126 | |
1 126 | -1 -126 |
2 63 | -2 -63 |
3 42 | -3 -42 |
6 21 | -6 -21 |
7 18 | -7 -18 |
9 14 | -9 -14 |
Step 6: Find out which factor pair sums up to $\color{blue}{ b = 24 }$
Step 7: Because none of these pairs will give us a sum of $ \color{blue}{ 24 }$, we conclude the polynomial cannot be factored.