4x-3y的2次方=3x-2y的2次方,并且xy 0
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6xy³-9x²y²-y^4=-y²(-6xy+9x²+y²)=-y²[(3x)²+2×3x×(-y)+(-y)&sup
2的x次方=4的(y+1)次方=>2的x次方=2的2(y+1)次方=>x=2(y+1)27的y次方=3的(x-1)次方=>3的3y次方=3的(x-1)次方=>3y=x-1x=4,y=1x-y=3再问:
x+9y=y-3x4x=-8yx=-2y则x²=4y²所以原式=(4y²-y²)/(4y²+y²)=3y²/5y²=3/
解题思路:本题目主要考查指数的运算,其中的关键是通过提取负号把y-x转化成-(x-y)解题过程:
x^4-kx^3y+2x^2y-3x^3y+y^4=x^4-(k+3)x^3y+2x^2y+y^4因为不含x^3y这一项(即系数为零)k+3=0k=-3
=2的(2x+5y)次方=2的3次方=8
2X^2+23XY-19Y^2^2表示平方.
2(x-y)-(x-3y)=1/22x-2y-x+3y=1/2∴x+y=1/24的x次方×2的y次方×2的y次方-2×2的2x次方×2的2y次方=2的2x次方×2的2y次方-2×2的2x次方×2的2y
原式=[(x-y)(x-y)+(x+y)(x-y)]/2x=(x-y)(x-y+x+y)/2x=(x-y)·2x/2x=x-y=3-1.5=1.5
9^2x-y+27^x-y=3^4x-2y+3^3x-3y=3^4x/3^2y+3^3x/3^3y=(3^x)^4/(3^y)^2+(3^x)^3/(3^y)^3=4^4/6^2+4^3/6^3=25
[x^m]^n=x^(mn)(xy)^m=x^m*y^mx^(2y)=(x^2)^y(2x)^y=2^y*x^yx^(3y)=(x^3)^y(3x)^y=3^y*x^y
原式=2y(x-y)²+4y²(x-y)³=2y(x-y)²[1+2y(x-y)]=2y(x-y)²(2xy-2y²+1)原式=(m-n)&
由题知a+2b=53a+4b=11解得a=1,b=2a+b=3a的2007次方·b³=8
4的y+1次方=2的2(y+1)次方27的y次方=3的3y次方x=2(y+1)3y=x-1x=4,y=1
(x+3y)(x-3y)(x²-9y²)=(x²-9y²)(x²-9y²)=(x²-9y²)²=x^4-18x
由题意得:2y+2=x,6y=x+2.解得:x=4,y=1.
【(x-y)的3次方-8(x-y)的2次方(x+y)+6y(x-y)的平方】/2(x-y)的平方=(x-y)²[x-y-8(x+y)+6y]/2(x-y)²=1/2(x-y-8x-