1.8=7-2y 2.5/12x-1/3=-1/4 3.1/9=x/3-1/6

已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) (3x+2y)(4x-5y)-12(x+y)(x-y)+7xy,其中x=2011,y=-1, 3x-y+x=3 4【X-y-1】=3【1-y】-1 5x-4y+4x=3 2x+y-3x=11 【 x除以2 】-【y 除以3】 =2 2x+7y-3x=19 x+y+x=12 3x+2y-x=18 解方程组（1）2x+3y=12 ,2x+y=0 (2)x+y=7,3（x+y）-7y=7 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 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x (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 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 方程题4道1.4(x-y-1)=3(1-y)+3.5 (x/2)+(y/3)=2 2.2(x-y)/3-(x+y)/4=13/6 6(x+y)-4(2x-y)=16 3.3x-y+z=3 2x+y-3z=9 x+y+z=12 4.5x-4y+4z=13 2x+7y-3z=19 3x+2y-z=18 若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值 x-y/7 - x+y/10 =1/2 2(x-y)-5(x+y)=3修改、、、、（x-y)/7-(x+y)/10=1/2 2(x-y)-5(x+y)=3 若x-y=2(x+y),求代数式x-y/x+y+x+y/x-y求代数式 x+y分之x-y+x-y分之x+y 已知:y=ax的3次方+bx+3,当x=-1/2时,y=-7,试求x=1/2时,y的值 2x—3y+5=0 3x+2y=12 y=2x 7x—3y=4 Y+1=三分之x+1 2x—3y=1 方程组 1、x+2y+z=4x+y+z=102x+3y-z=12、2x-3y+4m=113x+2y+5m=21x+3y+7m=20 解方程组:(x+3)(y-2)=(x-3)(y+10),(x+1)(y+3)=(x-2)(y+12) 解方程：（x+3)(y-2)=(x-3)(y+10) (x-1)(y+3)=(x+2)(y+12) 7x-3y/5=5x-y/3-x+y/2 x-1/5=y+1/3 { x-y/7-x+y/10=1/2 {2(x-y)+5(x+y)=3