Question

can anyone help me with factoring polynomials? 10u^2-3-u. For some reason I'm just not getting the process.

Answer 1

10u^2 - u - 3

you need to find two numbers which have a product of -3 and also you need to use some factors of 10 which when combine with factors of -3 to add/subtract to give the coefficient of u which is (-1).

these are 2 and 5 and -3 and +1:
2 *-3 and +1 * 5
so your factors are

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

Answer 2

you ok with that? its a bit hard to put into words

Answer 3

I'm trying to think through it. we were taught to multiply the coefficient of the a^2 value and the product, then look for pairs that added/subtracted to be the value in the middle. So yeah, sounds the same--i guess i was having trouble with the splitting up part

Answer 4

somehow using the same process I'm getting some right and some wrong, so i'm trying to figure out why that is, haha. thanks.

Answer 5

if i can ask you another question, we were told that once we find the factors of the multiples of the first and last term, we put them into the equation for the middle term (here u, so i would make it 10u^2+5u-6u-3) and then factor by grouping. is there a good way to tell which side the two terms in the middle should be on? I think that might be my issue.

Answer 6

oh right that seems a good way - well the terms with coefficients 6 and 3 should go together as should terms with 10 and 5
so u proceed
5u(2u+1) - 3(2u+1)
= (5u-3)(2u+1)

i see - you chose -6u and 5 u because of the difference = -u

Answer 7

yup - thats a good way of doing these - not seen it before

Answer 8

thanks for your help!

Answer 9

yw