It seems that $ 4x^{2}-6x-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 $\color{blue}{ a = 4 }$ by the constant term $\color{blue}{c = -9} $.
$$ a \cdot c = -36 $$Step 3: Find out two numbers that multiply to $ a \cdot c = -36 $ and add to $ b = -6 $.
Step 4: All pairs of numbers with a product of $ -36 $ are:
PRODUCT = -36 | |
-1 36 | 1 -36 |
-2 18 | 2 -18 |
-3 12 | 3 -12 |
-4 9 | 4 -9 |
-6 6 | 6 -6 |
Step 5: Find out which factor pair sums up to $\color{blue}{ b = -6 }$
Step 6: Because none of these pairs will give us a sum of $ \color{blue}{ -6 }$, we conclude the polynomial cannot be factored.