化简成：45x+9y=324 -x+9y=2两式相减：x=7 y=1
3X+3Y+2X-2Y=36(3X+2X)+(3Y-2Y)=365X+Y=36 (1)4X+4Y-5X+5Y=2(4X-5X)+(4Y+5Y)=2-X+9Y=2 (2)(1)+(2)*55X+Y-5X+45Y=36+1046Y=46Y=1X=9Y-2=7
5x+y=369y-x=2
