若2x+3y=5,则6-4x+6y=?

若5x+3y=3x+4y=x+2y+6,则x+y=___ 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 若|5x+2y-12|+（3x+2y-6）（3x+2y-6）=0,则2x+4y= 若(5X+2Y-12)(5X+2Y-12)+|3x+2y-6|=0,则2x+4y=? 4x-2y-6y*-y-3x+5y* *=2 就是平方 x+y/2+x-y/3=6,4(x+y)-5(x-y)=2用加减消元法解方程组