(3x+2y)/4=(2x+y)/55*(3x+2y)=4*(2x+y)15x+10y=8x+4y7x= -6yx= -6/7y(2x+y)/5=(x-y+1)/66*(2x+y)=5*(x-y+1)12x+6y=5x-5y+57x= -11y+5把x= -6/7y 带入上式:7*( -6/7y )=-11y+5-6y=-11y+55y=5y=1因为x= -6/7y y=1所以x= -6/7y