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February 28, 2015

February 28, 2015

Posted by **Anonymous** on Thursday, February 23, 2012 at 8:54am.

8/(21-y) = 12/(y+19)

I think the answer is y = 5, i just need to know how to do work out. i done some solution like this

first multiply by(21-y)(y+19)(assuming that y = 21 and y = 19:

(21-y)(y+19)8/(21-y) = (21-y)(y+19)12/(y+19)

then cancel and multiply out the brackets:

8(y+19) = 12(21-y)

that is

8x+152 = 12x-96

finally,rearrange the equation as

160x = 104

- math -
**MathMate**, Thursday, February 23, 2012 at 9:56amy=5 is correct.

To multiply by (21-y)(y+19), y must*not*equal 21 nor -19.

Correct until

8(y+19) = 12(21-y)

Expand:

8y+152=-12y+252

20y=100

y=5

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