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Subtracting algebra fraction help!!

Hi can someone please answer this question for me an explain the steps taken. Im working my way through k a strouds foundation book an he has a worked example but not explained and i cant get my head around it.

The question is
y+x/8x - y-x/4x

Alternatively

(y+x) (divided by) 8x - (y-x) (divided by) 4x
Original post by Rjamesb
Hi can someone please answer this question for me an explain the steps taken. Im working my way through k a strouds foundation book an he has a worked example but not explained and i cant get my head around it.

The question is
y+x/8x - y-x/4x

Alternatively

(y+x) (divided by) 8x - (y-x) (divided by) 4x


is it an expression or is there meant to be an answer?
Reply 2
Avatar for Rjamesb
Rjamesb
OP
Original post by surina16
is it an expression or is there meant to be an answer?

I think its simplfying
The final answer is
3/8 - y/8x
Original post by Rjamesb
I think its simplfying
The final answer is
3/8 - y/8x


okay :smile: :

1. to subtract fractions you need a common denominator.
the denominators are 8x and 4x, and although you would normally cross-multiply, it would be easier here to just multiply the second fraction by 2/2 so you get:
(y+x)/8x - (2y-2x)/8x
2. combining this into 1 fraction you get:
(y + x - 2y + 2x)/8x
It is +2x because you are subtracting a negative value
3. simplify the numerator:
(3x - y)/8x
I would leave it like this but your book takes it further so:
4. this is equivalent to:
3x/8x + -y/8x
The first fraction simplifies so you get:
3/8 - y/8x :smile:
Reply 4
Avatar for Rjamesb
Rjamesb
OP
Original post by surina16
okay :smile: :

1. to subtract fractions you need a common denominator.
the denominators are 8x and 4x, and although you would normally cross-multiply, it would be easier here to just multiply the second fraction by 2/2 so you get:
(y+x)/8x - (2y-2x)/8x
2. combining this into 1 fraction you get:
(y + x - 2y + 2x)/8x
It is +2x because you are subtracting a negative value
3. simplify the numerator:
(3x - y)/8x
I would leave it like this but your book takes it further so:
4. this is equivalent to:
3x/8x + -y/8x
The first fraction simplifies so you get:
3/8 - y/8x :smile:

Thanks alot for that, that was a great help
Original post by Rjamesb
Thanks alot for that, that was a great help


no problem! PM me anytime if you need help :smile:

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