（x-4y=-1 2x+y=16) (x-y=1 2x+y=5 )

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 若x-y=1 化简（x+y)(x^2+y^2)(x^4+y^4)(x^8+y^8)(x^16+y^16) {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=? 4x+2y=16 x-y=1, （x-4y=-1 2x+y=16) (x-y=1 2x+y=5 ) 初二上学期方程题 4x+y=5 5x+4y=63x-2y=1 2x+3y=13x-2y=7 7x+5y=32x+3y=17 2x-y=-4x+5y=6 2x+y=23x-6y=4 3x+2y=52x+y=73x-4y=53x+y=1x-2y=-1x+y=42x+3y=92x-3y=74x+5y=3x+y=20004x+6y=90003x+5y=113x-2y=42x+3y=215x-2y=5x+y=54x+3y=182x+3y=16x+4y=132x+3y=40x 2(x-y)/3-(x+y)/4=-1 (1) 6(x+y)-4(2x-y)=16 (2) 解方程组2(x-y)/3-x+y/4=-1 6(x-y)-4(2x-y)=16 解方程组：2(x-y)/3-x+y/4=-1 ,6(x+y)-4(2x-y)=16 2(X-Y)/3=(X+Y)/4 -1 6(X+Y)=4(2X-Y)+16解方程 6(x+y)=4(2x-y)+16,2(x-y)/3=x+y/4-1 2(x-y)/3—x+y/4=1 6(x+y)—4(2x-y)=16 3分之2(x-y)-4分之x+y=-1 8(x+y)-4(2x-y)=16 (2x-2y)/3-(x-y)=-1和6(x+y)-4(2x-y)=16 3分之2(X-Y)-4分之X+Y=-1,3(X+Y)-2(X-Y)=16 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x-4y)(2x+y)=