①7x-3y=1,②-5x+6y,
① X+Y=3 Y=2X-3 ② x+2y=9 y-3x=1 ③3/x+1=y 2(x+1)=6 ④ y-x=3 7x-
x+y=3 x+2y=9 3/x+1=y y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9
①{2X-5y=21,②{2x+y=6,③{x-3y=1,④{y=-2x=3 {y=-x.{y=1/2x+1.{5x-9
①7x-3y=1,②-5x+6y,
解二元一次方程.①y=2x-3 3x+2y=8 ②y=x+2 6x+5y=-1 ③3x+5y=11 x+4y=15
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
3x+4y=6①,x+2y=4② 2x+5y=16①,8x-7y=10②
解方程组:①3x-7y=1,5x-4y=17②23x+17y=63,17x+23y=57
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.
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
解方程一;{x+y-z=6,x-3y+2z=1,3x+2y-z=-7.②{3x+4z=7,2x+3y+z=9,5x-9y
(3x-4y)(5x-4y)-(7x-8y)(6y-5x)