Question 503111
hi 
I would like to know if I solved this equation correctly: 
3x+y=25 where x-y=7 what is the value of y. 
This is how I answered;
y=7-x 
3x+ (7-x)=25 
2x+7=25
2x+7=25
2x=18
x=9 
y=7-9
y=-2 
(x,y)= (9,-2) 
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You don't need to ask, just sub your answer into the equations.
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3x+y=25
3*9 - 2 = 25  That works.
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x-y=7
9 - (-2) = 7
11 = 7  uhoh.  It's not correct.