计算(2x+3y+4)(2x+3y减4)
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(1)=(x-y)(x+1)(x-1)(2)=x(x^2+x+1/4x)=x(x+1/2)^2(3)=4x^2+4xy+y^2-x^2+4xy-4y^2=3x^2+8xy-3y^2=(3x-y)(x+
两个式子作差得到x=5带入得到y=23
-x^y^7+y^8)(这里有问题,x的几次方?再问:就是一次方再答:(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-xy^7+y^8)(x^2+xy+y^2)=(x^8-x^7y+x^
X(11Y-2X)
2x^2y^3+(4x^2y^3)-(-3x^2y^3)=x^2y^3[2+4-(-3)]=9x^2y^3再问:计算:2x^2y^3+(4x^2y^3)-(-3x^2y^3)再答:(⊙o⊙)…没有X,
(x-3y)(y+2x)-(4y-3x)(3x+4y)=2x^2-3y^2-5xy+9x^2-16y^2=11x^2-5xy-19y^2
(x+y)(x+y)^2(-x-y)^3=-(x+y)^6
(4x²y--9y)/(2x+3)=y(2x+3)(2x-3)/(2x+3)=y(2x-3)
(-x-2y)*(3x-y)=-3x^2-5xy+2y^2
原式=3x-4y+(2y+x)-(x-3y)-6x=-3x-4y+(2y+x)-(x-3y)=-3x-4y+2y+x-x+3y=-3x+y
16(x+y)^8/9(x-y)^8=16/9*[(x+y)/(x-y)]^8哪个好理解用哪个.再问:有过程没。。。再答:这个过程其实没什么好研究的。。。[3(x-y)^2(x+y)^-2/4(x+y
原式=(2x²+8xy-3xy-12y²)-(3x²-6xy+xy-2y²)=2x²+8xy-3xy-12y²-3x²+6xy-x
解题思路:根据完全平方公式和平方差公式进行计算 .解题过程:
1/(x-y)-1/(x+y)-2y/(x^2+y^2)-4y^3/(x^4+y^4)-8y^7/(x^8+y^8)=【(x+y)-(x-y)】/(x-y)(x+y)-2y/(x^2+y^2)-4y^
8x²y^4(-3x/4y²)/(-x²y/2)=2x²(-3x)y²/(-x²y/2)=12xy
解代数式得:-3x的平方y-2y的三次方因为1/2的平方=-1/2的平方,所以结果仍正确给分吧!嘿嘿!
[(2x-3y)^2-(x-y)(4x+2y)]/2y=[(4x^2-12xy+9y^2)-(4x^2-2xy-2y^2)]/2y=(-10xy+11y^2)/2y=(11y-10x)/2
原式=(3x+y+3x-y)(3x+y-3x+y)÷2(2x-y)=12xy÷2(2x-y)=6xy/(2x-y)
3x-2y-[-4x+(z+3y)]=3x-2y-(-4x+z+3y)=3x-2y+4x-z-3y=7x-5y-z
=12x^2-3xy+6x+4xy-y^2+2y-8x+2y-4=12x^2-y^2+xy-2x+4y-4