2y乘以1 2y减一的差减去3y成语1 3y 2 3的和.解答过程是
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当x>y时答案是2分之5当xy时x-y=2y当x
((x-y)(x+y))^2=(x^2-y^2)^2=16,平方差公式
124²-123*125=124²-(124-1)(124+1)=124²-124²+1=1(x+2y)²-(x+y)(3x-y)-5y²=
X=7or-7Y=3or-3
1.x^2-1/y2.3/a+11/33.x^2-y^24.x减去y的平方(de)差:x-y^25.1/(x+y)
3xx-2xy-8yy=0(3x+4y)(x-2y)=0所以(3x+4y)=0或(x-2y)=0所以x=-4y/3或x=2y所以x/y=-4/3或2
设x=3,y=2等于4/65
9m2+12my+4y2-z2
答:x²(x-y)+y-x=(x²-1)(x-y)=(x-1)(x+1)(x-y)
(x^2-4y^)\(x+y)^2乘以2x(x+y)/(x+2y)=2x(x-2y)\(x+y)
3x/(x-4y)+(x+y)/(4y-x)-7y/(x-4y)=3x/(x-4y)-(x+y)/(x-4y)-7y/(x-4y)=(3x-x-y-7y)/(x-4y)=(2x-8y)/(x-4y)=
5×(-5)²-3×(-5)-60=80
(x^3-3x^y+3xy^2-y^3)-(x^3+3x^y+3xy^2+y^3)=x^3-3x^y+3xy^2-y^3-x^3-3x^y-3xy^2-y^3=-6x^y-2y^3
3x²y-(-5xy²)=xy(3x+5y)
3y^2-2y-1=0y^2-2y/3-1/3=0(y-1/3)^2-4/9=0y-1/3=±2/3解得y1=-1/3y2=1请注意,最后的1和2是下标,电脑没法打
已知X+Y=2----(1)4X-Y=1----(2)由(1)+(2)得5x=3x=3/5y=7/54x^2y-4xy+xy^2=xy(4x-1+y)=3/5*7/5(4*3/5-1+7/5)=84/
3x^(m+1)*y^(m+n)-9x^2m*y^(2n-3)=ax^2m*y^(m+n)所以3-9=a,m+1=2=2m,m+n=2n-3所以a=-6,m=1,n=4如果不懂,祝学习愉快!
(4x/z)-(5y/z)=-2……①(x/z)-(4y/z)=3……②方程②×4得,(4x/z)-(16y/z)=12……③①-③得,11y/z=-14,∴y/z=-14/11代入②得,(x/z)-