Question

I need help with factoring I have the problem: 4x^2 + 7xy -15y^2 , I think I understand it mostly but I dont get how to get the 7xy?

Answer 1

best bet is to forget about it to start with; factor it like normal

Answer 2

so take away the y's?

Answer 3

4(15) = 60 ; what factors of 60 subtract to get 7?

Answer 4

nah, not take away, just ignore them for the moment

Answer 5

1,60
2,30
4,15
3,20
6,10
12,5 .... hmmm 12-5 = 7 right? we can use them

Answer 6

so is it not 4 and 15 can you use other factors of it? im sorry i have a really hard time at math

Answer 7

set it up like its going to work: we got the xs in front and the ys in back sooo

(x+12y)(x-5y) but we used that 4 in the beginning so lets divide it back out

(x+12y/4)(x-5y/4) simplify the fractions and if its still a fraction, throw the bottom in front

(x+3y)(4-5y)

Answer 8

i havent tried other factor; you use 4 and 15 since that is what the problem gies you to work with and you can be assured that itll mostly work out

Answer 9

4 and 15 get us a number that we can use; and the factors of that number are important to us

Answer 10

4(15) = 60; factors of 60 are:

1,60
2,30
4,15
3,20
6,10
12,5

Answer 11

opps dropped an x :)

(x+3y)(4x-5y) thats better

Answer 12

any questions?

Answer 13

im going to work it out im having a really hard time understanding factoring so before i bother with questions i want to see if i can figure it out but thanks for helping im going to try to work out a few more problems and ill ask again if i need help are you paid to be on here or your just here because your really helpful is all thanks so so much!

Answer 14

just my free time, and the library is open so I use the internet :)

Answer 15

well then you should be paid i went to the math lab at school for help last night and you did more :) than they did so thanks for sure

Answer 16

thanx and youre welcome :)