Question

im so confused with the changing of signs. :(
how do you do this? factorise ac-3c+6b-2ab

Answer 1

distributive property? :/

Answer 2

i don't get it :( why must a = (a-3), b = 2b, c = c. where did u get all those numbers....

Answer 3

okay :) hey, i did it this way but i didn't get the ans :/
ac-3c+6b-2ab
=c(a-3)+2b(3-a)
=c(a-3)-2b(a-3)
=(c-2b)(a-3)


did i changed my signs wrongly or smth? :(

Answer 4

Wait...let me double check mine

Answer 5

You got it correct

Answer 6

I rushed my answer. Sorry. I will delete it.

Answer 7

okay.. hey but i did it another way and i got this!
ac-3c+6b-2ab
=ac-3c-2ab+6b
=c(a-3)-2b(a+3)
=c(a-3)+2b(a-3)
=(c+2b)(a-3)


which is correct? :/

Answer 8

wait ....

Answer 9

Your step three is wrong. The way you did it the very first time is correct.

Answer 10

why? :( how do you know? sorry, i know i ask a lot...

Answer 11

In your step three, when you distribute the negative you would get (-a-3) not (a-3)

Answer 12

-(a+b) = -a+-b=-a-b

Answer 13

okay.. hey but i did it another way and i got this!
0. ac-3c+6b-2ab
1. =ac-3c-2ab+6b
2. =c(a-3)-2b(a+3)
3. =c(a-3)+2b(a-3) <---- Incorrect distribution of negative
4. =(c+2b)(a-3)

Answer 14

:o ! actually i think my step 2 is wrong.
ac-3c+6b-2ab
1. =ac-3c-2ab+6b
2. =c(a-3)-2b(a+3 ) --> this should be c(a-3)-2b(a-3) . is it correct?

Answer 15

ac - 3c + 6b - 2ab
c( a-3) +2b( 3 - a)
c(a -3 ) -2b( a-3)
(a-3) (c -2b)....i think Cherry did it right!

Answer 16

c(a-3)-2b(a+3) is correct because you only factor out a positive 2b. c(a-3)-2b(a-3) is incorrect because once again, you factored out a positive 2b. You didn't factor out any negatives. Here's your step 1 re-written with parentheses:

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

Answer 17

heyhey thanks guys :) esp heromiles for trying to explain the steps to me.:) i rly apprecite it.

Answer 18

You're very welcome