How do you factor 4x^2-4x-15?

2 Answers
Mar 19, 2018

the answer is (2x+3)(2x-5)

Explanation:

for this, you have to multiply the first number and the last number so that you have to find two numbers that multiply to give you that but add yo give you the middle one. so you have to find two numbers that multiply to give you60 and add to -4 which is -10,6 so now put it in the equation 4x^2-10x+6x-15 now group it (4x^2-10x)(6x-15) now take out. 2x(2x-5)+3(2x-5) so now you'll left with your answer. since the inside ones are the same, you count them as one.

Mar 19, 2018

4x^2-4x-15=color(blue)((2x+3)(2x-5)

Explanation:

Factor:

4x^2-4x-15

Factor by splitting the middle term.

Multiply the coefficient of the first term (4) by the constant term (-15).

4xx-15=-60

Find two factors of -60 that add up to -4. The numbers color(red)6 and color(blue)(-10 meet the requirement.

Split -4x as the sum of color(red)(6x and color(blue)(-10x.

4x^2+color(red)(6x)-color(blue)(10x)-15

Factor out the common term from the first two terms and the second two terms.

2x(2x+3)-5(2x+3)

Factor out the common term (2x+3).

(2x+3)(2x-5)