Question

factor completely. 5x^2 + 19x - 4

Explanation:

Step1: Multiply leading - coefficient and constant

$5\times(-4)=-20$

Step2: Find two numbers for $-20$ that sum to 19

The numbers are 20 and - 1 since $20\times(-1)=-20$ and $20+( - 1)=19$

Step3: Rewrite the middle term

$5x^{2}+20x - x - 4$

Step4: Group the terms

$(5x^{2}+20x)-(x + 4)$

Step5: Factor out the GCF from each group

$5x(x + 4)-1(x + 4)$

Step6: Factor out the common binomial factor

$(5x - 1)(x + 4)$

Answer:

$(5x - 1)(x + 4)$