Step 1 :
After factoring out $ n $ we have:
$$ 2n^{3}+3n^{2}+n = n ( 2n^{2}+3n+1 ) $$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 = 1} $.
$$ a \cdot c = 2 $$Step 4: Find out two numbers that multiply to $ a \cdot c = 2 $ and add to $ b = 3 $.
Step 5: All pairs of numbers with a product of $ 2 $ are:
PRODUCT = 2 | |
1 2 | -1 -2 |
Step 6: Find out which factor pair sums up to $\color{blue}{ b = 3 }$
PRODUCT = 2 and SUM = 3 | |
1 2 | -1 -2 |
Step 7: Replace middle term $ 3 x $ with $ 2x+x $:
$$ 2x^{2}+3x+1 = 2x^{2}+2x+x+1 $$Step 8: Apply factoring by grouping. Factor $ 2x $ out of the first two terms and $ 1 $ out of the last two terms.
$$ 2x^{2}+2x+x+1 = 2x\left(x+1\right) + 1\left(x+1\right) = \left(2x+1\right) \left(x+1\right) $$