Question

{2(3x-2y)+1=7x
{12(x+y)-15=7x+12y
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Answer 1

$\displaystyle \left \{ {{2(3x-2y)+1=7x} \atop {12(x+y)-15=7x+12y}} \right. \\\\\left \{ {{6x-4y+1=7x} \atop {12x-15=7x}} \right.\\ \\\left \{ {{6x-4y+1=7x} \atop {x=3}} \right. \\\\6*3-4y+1=7*3\\\\y=-\frac{1}{2}\\ \\(x,y)=(3,-\frac{1}{2})$