It seems that $ -8x^{2}+7x-56 $ cannot be factored out.
Step 1 :
After factoring out $ -1 $ we have:
$$ -8x^{2}+7x-56 = - ~ ( 8x^{2}-7x+56 ) $$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 $\color{blue}{ a = 8 }$ by the constant term $\color{blue}{c = 56} $.
$$ a \cdot c = 448 $$Step 4: Find out two numbers that multiply to $ a \cdot c = 448 $ and add to $ b = -7 $.
Step 5: All pairs of numbers with a product of $ 448 $ are:
PRODUCT = 448 | |
1 448 | -1 -448 |
2 224 | -2 -224 |
4 112 | -4 -112 |
7 64 | -7 -64 |
8 56 | -8 -56 |
14 32 | -14 -32 |
16 28 | -16 -28 |
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.