(y-1)/x=7/8

x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x 已知(3x+1)(3x-3)-3x+2)^2=-7,(y+7)(y-7)-y(y-7)=0,求8y^2-5y(-y+3x)+4y(-4y-5/2x)的值 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 x+2y=2x+y+1=7x-y 求：2x-y? 例X=1 y=21.X+Y=5 X-Y=15 2.2X+3Y=4 5X+6Y=7 3.X+3Y=5 3X+Y=-1 4.2X+Y=3 3X+5Y=11 5.4X+3Y=6 2X+Y=4 6.X+Y=180 X=3Y-10 7.3X-2Y=3 2X-Y=7 8.5X+3Y=7Y X+Y=45 9.3X+4Y=126X+8Y=24 X:6Y=1:4 10.X+Y=138 X-45=Y+53 11.X+Y=60 14Y=20X 12.2X+3Y=15.5 5X+6Y=35 13.X+Y=170 3 1 已知x+y/y=7/3 求x+y/x-y等于什么2 若x+4/3=y+3/2=z+8/4 且x+y+z=12 求x、y、z的值 计算:1/(x-y)-1/(x+y)-2y/(x^2+y^2)-4y^3/(x^4+y^4)-8x^7/(x^8+y^8) 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) 解二元一次方程{5X-2y=3 X+6y=7 {5x+4y=-3 2x-3y=8 {x+Y+Z=26 x-Y=1 2x-Y+z =18{x/3+Y/5=3 X/2- 2Y/5=1 快 1 .{5X-2y=3 X+6y=7 2.{5x+4y=-3 2x-3y=8 3.{x+Y+Z=26 x-Y=1 2x-Y+z =18 4.{x/3+Y/5=3 X/2- 2Y/5=1 y=2x-3 3x+2y=3 5x-2y=3 x+6y=11 二分之x三分之y+=-3 7x=8y-4 3x+2y=1 2x-y+2z=-4 x+2y-z=3[y=2x-3 3x+2y=3] [5x-2y=3 x+6y=11] [二分之x三分之y+=-3 7x=8y-4] [3x+2y=1 2x-y+2z=-4 x+2y-z=3] (2) 5分之x+2分之y=6分之5,x+y=3 6x-7y=--2.5x-2y=-0.9三元一次方程组(1)x+y+z=1,x-y+z=3,x+y-z=-1 （1）x-y=3,x+2y+z=8,2x-y-3z=1 (3) 3(2x-y)+4(x-2y)=87,2(3x-y)-3(x-y)=82麻烦再接解道题3(2x-y)+4(x-2y)=87，2(3x-y)-3(x-y)=82解三元一 x+y=5① x=3y+2① 9x-5y=1① 3x-2y=11① x-2y=y+1① 2x-y=7② x+3y=8② 6x-7y=2② 2x+3y=16② 2x-3y=10②3x+2y=y+1①2x-3y=10②D 解方程组1.x+1/3=5x-y/5 7y=5x+25 (x=2,y=5) 2.2x-y/5=x+y/3=3(x=8,y=1) 用适当的方程解方程组2(x+y)-(x-y)=8 (x+y)-2(x-y)=15 2x+1=5(y+2) (3x+2)-2(y+7x)=16 函数的值域(1)y=3x (2)y=8/x (3)y=-4x+5 (4)y=x^2-6x+7 同志们 ... 请解答方程组：（39）2x+y=5 (40)x+y=7 (41)2x+3y=12 (42)2x+y=3ax+3y=7 2x-y=8 3x+4y=17 3x-5y=11(43)3x+y=82 (44)3(x-1)=y+5 45 x/4+y/3=7 (46)x+y/3 +x-y/2=610x-11y=87 5(y-1)=3(x+5) 2/3x+y/2=14 3(x+y-)2(x-y)=28 (x+y)/8=x/3-1 2/7-y-x/2=2 (x+y)/8=x/3-1 2/7-y-x/2=2