<PRE><B>Question 1084297</B>
(1) 3x+y=1
   -6x-3y=-2
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9x + 3y = 3  ---- 1st eqn times 3
-6x -3y =-2
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3x = 1
x = 1/3
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3x+y=1
3*(1/3) + y = 1
y = 0
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Do the others the same way.
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(2) 3x-5y=15
    x-2y=8

(3)-2x+y=5
    8x-4y=12

(4)2(x+1)=-3y+a
   3y-10=-4y

(5) 3(x-2)+2y=5
    6y=2x

(6)5x-2y=4
    y=-3x+a

(7)4x=5y=0
   8(x-1)=10y</PRE>