How do you factor 15x^4-50x^3-40x^215x450x340x2?

1 Answer
May 25, 2016

5x^2 ( 3x + 2 ) ( x - 4 )5x2(3x+2)(x4)

Explanation:

Look for the greatest common factors of all the numbers/letters. in this case, 55 is common to 1515, 5050, and 4040, and x^2x2 for the xx's giving you:

5x^2 (3x^2 - 10x - 8)5x2(3x210x8)

Since you have a number greater than 11 for the x^2x2 inside the brackets, you can factor it further by determining what two number add up to -1010 and multiply to -2424 (derived from 3 xx (-8)3×(8)).

44 and 66 won't work because of the negative numbers, however, -1212 and 22 will.

5x^2 ( 3x^2 - 12x + 2x - 8)5x2(3x212x+2x8)

Look for the GCFs in the first two variables inside the brackets and then the second two.

5x^2 [ ( 3x (x - 4) + 2 (x - 4) ]5x2[(3x(x4)+2(x4)]

Collect like terms and simplify

5x^2 (3x + 2)(x - 4)5x2(3x+2)(x4)