Question

Factor this expression. Check by multiplying factors.
Medal rewarded for step by step procedures.

2ab-6ac+3b-9c

Answer 1

first rearrange
2ab + 3b - 6ac - 9c
now can you factor the first 2 and the last 2 terms to get a common factor?

Answer 2

I don't know how to factor.

Answer 3

2(a+3)(b-3c)?

Answer 4

first factor 2ab + 3b

b is common to both terms and 2ab / b = 2a and 3b / b = 3 so we can write

2ab + 3b = b(2a + 3)

Answer 5

-6ac - 9c

take out -3c and we get
-3c(2a + 3)

Answer 6

Why are we taking out -3c?

Answer 7

because its the highest factor which will divide into both -6ac and - 9c

Answer 8

Alright, I'm following. So, we just put those two terms together?

Answer 9

yes so we have
b(2a + 3) - 3c(2a + 3)

now 2a + 3 is common to both parts so we have

(b-3c)(2a+3)
and theres your factors

Answer 10

Okay, I get it, but what do I do when an expression like this comes up?

3ab +3ac+2b^2+2bc

Answer 11

take out 3a for the first 2 and 2b for the last 2 terms

the highest common factor is called the HCF (or GCF in the States)

Answer 12

this ves you 3a(b + c) + 2b(b + c)

Answer 13

same priciple as the first question

Answer 14

So then we have 3a+2b

Answer 15

correct? @cwrw238

Answer 16

thats in one of the brackets
the factors are (3a + 2b)(b+ c)

Answer 17

if you multiply this out it should come back to the original expression

Answer 18

Oh yeah, that's right.. I'm forgetting some steps :(

Answer 19

3a*b = 3ab
2b*c = 2bc
3ab+2bc.. Like that?

Answer 20

first multiply the ( b +c) by 3a then by 2b
yes

Answer 21

3ab+3ac+2b^2+2bc

Answer 22

3a*b + 3a*c + 2b*b + 2b*c
= 3ab+ 3ax + 2b^2 + 2bc

Answer 23

yea - 3ab not 3ax - my mistake

Answer 24

I mean 3ac - lol!

Answer 25

Oh well, we got the original expression back so (3a + 2b)(b+ c) is correct?

Answer 26

Just double checking before I put in.

Answer 27

yes

Answer 28

hope this has helped - i gotta go right now

Answer 29

thanks alot man! I might have you go over some of my work 'cause I'mma go try a few.

Answer 30

i'm a ma'am - but thats ok!

Answer 31

Sorry madam.