<PRE><B>Question 230499</B>
3x+5y=21
2x-y=1, y=2x-1
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3x+5(2x-1)=21
3x+10x-5=21
13x=26
x=2
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2(2)-y=1
4-y=1
-y=-3
y=3
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proof
3(2)+5(3)=21
6+15=21
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