Question

factor completely. $5x^2 - 6x - 8$

Explanation:

Step1: Find product of a and c

$a=5, c=-8$, so $5\times(-8)=-40$

Step2: Find two factors of -40

Factors: 4 and -10 (since $4+(-10)=-6=b$)

Step3: Split middle term

$5x^2 + 4x -10x -8$

Step4: Factor by grouping

$x(5x + 4) -2(5x + 4)$

Step5: Factor out common binomial

$(5x + 4)(x - 2)$

Answer:

$(5x + 4)(x - 2)$