Asked by ann

4x+y==21
7x-4y=8
Answered by ann
4x+5y=5
x=y-10
Answered by John
4x+y=21
7x-4y=8
21*8=168
-------------
8(4x+y)=21(7x-4y)
Solve
Answered by Steve
John's idea is interesting, but leaves you no closer to the solution.

4x+y=21
7x-4y=8

Consider his multiplication idea, and work it this way:

28x+7y = 147
28x-16y = 32
Now subtract to get
23y = 115
y = 5
now you can find x easily.

The other set is even simpler. You know what x is, so plug it in:

4(y-10)+5y=5
4y-40+5y=5
9y=45
y=5
Now get x
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