4x-2y＝5 3x-4y＝15-搜答案-搜搜做题作业网

(2x-y)²-4(x-y)(x+2y)

写清楚点点比如说前面是X/X还是X/(X-Y)打上括号分段这样才能清楚的做

(x-y)(z+y-x+y+2y)÷4y=(x-y)(z-x+4y)÷4y{(x+y)(x-y)-(x-y)的2次方+2y(x-y)}除以4y=(x-y)(x+y-x+y+2y)÷4y=(x-y)(4

2（x+2y）＝x²+y²+5整理得(x-1)^2+(y-2)^2=0x=1,y=2(x²+y²)/(3x-4y)=-1

(x^2-y^2)/(x+y)-(4x(x-y)+y^2)/(2x-y)=(x-y)(x+y)/(x+y)-(4x^2-4xy+y^2)/(2x-y)=(x-y)-(2x-y)^2/(2x-y)=(x

[（x+y）2-（x+y）（x+3y）-4y2]÷2y，=[x2+2xy+y2-x2-3xy-xy-3y2-4y2]÷2y=（-2xy-6y2）÷2y=-x-3y，当x=-2，y＝12时，原式=-（-

已知x－y＝1,则y=x-1,x=y+1｛(x＋2y)²＋（2x＋y）(x＋4y)－3(x＋y）（x－y)｝÷y=（x²＋4xy+4y²＋2x²＋9xy+4y&

原式=1/4y[x^2-4*y^2-(x^2+8*xy+16y^2)]=1/4y(-8*xy-20*y^2)=-2x-5y代入得：原式=(-2)*(-2)-5(-3)=19

【（X²+Y²）-（X-Y）²+2Y（X-Y）】/4Y＝1,【2xy+2Y（X-Y）】/4Y＝14x-2y=42x-y=24X/(4X²-Y²)-1/

(2x-y)^2-4(x-y)(x+2y)

4x^2+y^2-4xy-4(x^2-xy+2xy-2y^2)展开化简吧!

4x(y-x)-y^2因式分解

4x(y-x)-y²=4xy-4x²-y²=-(4x²-4xy+y²)=-(2x-y)²很高兴为您解答,【the1990】团队为您答题.请点

原式=(x^2-4y^2-x^2-8xy-16y^2)/(4y)=-5y-2x=-25-4=-29

2x−y＝5①3x+4y＝2②，①×4得，8x-4y=20③，②+③得，11x=22，解得x=2，把x=2代入①得，2×2-y=5，解得y=-1，所以方程组的解是x＝2y＝−1．故答案为：x＝2y＝−

(2x-y)²-4(x-y)(x+y)=(4x²-4xy+y²)-4(x²-y²)=4x²-4xy+y²-4x²+4y&

“4y^2/x-y”应该是“4y^2/x-2y”吧x+2y+4y^2/x-2y+4x^2y/4y^2-x^2=(x+2y)+4y^2/(x-2y)+4x^2y/(2y-x)(2y+x)=(x+2y)+

解方程组3x+4y＝3x+y＝1，得x＝1y＝0．把x=1，y=0代入2mx+3y=2，得2m+0=2，∴m=1．故答案为1．

((x+y)-(x-y)+2y(x-y)=x+y-(x-2xy+y)+2xy-2y=2xy+2xy-2y=2y(2x-y)=2y×10=20y20y÷4y=5

(x+3y-4)(2x-y)

原式等于2x^2-xy+6xy-3y^2-8x+4y=2x^2+5xy-3y^2-8x+4y

①-②×3得x=9+6k，代入①得y=-8k+73，代入方程3x+15y=16+2k，得3（9+6k）-15×8k+73=16+2k，解得k=-1．