2x-7x=8 3x-8y-10=0

(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=4x-2y-z-5x[6y-(x+y)]+x-(3y-10z)=4x-2y-z-30xy+5x²+5xy+x-3

x-y/7-x+y/10=1/2两边乘7010x-10y-7x-7y=353x-17y=35(1)2(x-y)+5(x+y)=32x-2y+5x+5y=37x+3y=3(2)(2)*3-(1)*79y

8（x平方-2y平方)-x(7x+y)+xy=8x平方-16y平方-7x平方-xy+xy=x平方-4y平方=(x-2y)(x+2y)手机提问的朋友在客户端右上角评价点【满意】即可.再问：太棒了！连我这

两式相加2x-y+3x+y=7+85x=15x=3y=2x-7=2x3-7=-1如果本题有什么不明白可以追问,

设a=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)那么y=a*(x-10);那么y^=a^*(x-10)+a*(x-10)^=a^*(x-10)+a那么y

根号(x+y-8)+根号(8-x-y)=根号(3x-y-4)+根号(x-2y+7),根据二次根式有意义得：X+Y-8≥0,8-X-Y≥0,∴X+Y≥8,X+Y≤8,∴X+Y=8,左边为0,右边两个非负

-3(2x-y)-{7x-[6x+2y-(10x-8y)]-x-2(3x-4y)}=-6x+3y-7x+(6x+2y-10x+8y)+x+6x-8y=-13x+3y-4x+10y+7x-8y=-10x

2x-7y=8①3x-8y=10②①乘3得到6x-21y=24③②乘2得到6x-16y=20④③－④得－5y＝4y=－5分之4将y=－5分之4代入③得x=5分之6希望对你有帮助~望采纳,O(∩_∩)O

2x+y+z=10(1)x+2y+z=-6(2)x+y+z=8(3)(2)-(3):y=-14(4)(1)-(2):x-y=16(5)把（4）代入（5）：x+14=16x=2(6)把（4）和（6）代入

-8(2x-y)-{7x-[6x+2y-(10x-8y)]}=-16x+8y-[7x-(6x+2y-10x+8y)]=-16x+8y-(7x-6x-2y+10x-8y)=-16x+8y-7x+6x+2

解∵/y+5/+(5x+1)²=0∴y+5=0.5x+1=0∴y=-5,x=-1/5原式=-6x+3y-{7x-(10y-4x)-x-2(3x-4y)}=-6x+3y-[7x-10y+4x-

5x+2y=8①3x-y=7②，①+②×2得，11x=22，解得x=2，把x=2代入②得，6-y=7，解得y=-1，故此方程组的解为x=2y=-1．再问：你好再问：4x+7y=106x-11y+28=

(X+2)(X+5)(X-4)(X+2)(y-3)(y-4)(x+9)(x-2)

-3(2x-y)-{7x-〔6x+2y-（10x-8y）〕-x-2(3x-4y)}=-6x+3y-{7x-6x-2y+10x-8y-x-6x+8y}=-6x+3y-(4x-2y)=-10x+5y由(x

=x^2+10x-24+x^2+15x+56-x^2+5x+50=x^2+30x+82=4+60+82=146其实,不化简,直接代入=14*0+9*10+7*8=0+90+56=146也很简单

-3(2x-y)-｛7x-〔6x+2x-(10x-8y)〕-x-2(3x-4y)｝=-6x+3y-｛7x-〔8x-10x+8y)〕-x-6x+8y｝=-6x+3y-｛7x-〔-2x+8y)〕-7x+8

解二元一次方程组,①*2,然后①-2得出X=2Y=3则X-Y=-1X+Y=5

一、3x-5y=5……①3x-4y=23……②②-①得,y=18,把y=18代入①得,x=95/3∴x=95/3y=18二、2x-7y=8……①3x-8y-10=0……②①×3得,6x-21y=24…

等于.-3y-10x

很累-3x-2y