Question

question
factor completely.
$3x^2 - 26x - 9$

Explanation:

Step1: Find product of leading & constant terms

$3 \times (-9) = -27$

Step2: Find pair summing to middle term

We need two numbers that multiply to $-27$ and add to $-26$: $-27$ and $1$.

Step3: Split middle term

$3x^2 -27x + x -9$

Step4: Factor by grouping

$$\begin{align} &3x(x - 9) + 1(x - 9) \\ &=(3x + 1)(x - 9) \end{align}$$

Answer:

$(3x + 1)(x - 9)$