67.6k views
1 vote
Factor this:
18x^2+39x-15

2 Answers

5 votes

Steps for Factoring:

1) Find CM (common factor) for the expression: 3

Factor out 3 =>


3(6x^(2)+13x-5)

2)Factor the above expression by grouping:

The expression needs to be written as
6x^(2) + ax+ bx -5

a and b should add up to 13 and multiply up to -30 (6 × -5)

By Guess & Check we find that the pair is a = -2 and b = 15 (-2+15; -2 × 15)

3) Now we can rewrite
(6x^(2)+13x-5) as
(6x^(2) -2x)+(15x-5)\\

Factor out 2x in the first group and 5 in the second group:


2x(3x-1)+5(3x-1)\\

As 3x-1 is on both sides, now we can do the operation: 2x+5 (distributive property)

(3x-1) (2x+5)

The answer is 3(3x-1) (2x+5)

Hope it helps!

User Spirine
by
4.6k points
4 votes
answer is:
3(2x+5)*(3x-1)
User Cdog
by
5.3k points