(1)25(X+Y)^2-16(X-Y)^2

来源：学生作业帮编辑：神马作文网作业帮分类：数学作业时间：2024/11/17 23:04:07

(1)25(X+Y)^2-16(X-Y)^2
(2)(X+Y)^2-14Y(X+Y)+49Y^2
(3)a~3*X~2-C^3*X^2-a^2*Y^2+C^3*Y^2
(4)(二分之一*X+三分之二Y-四分之三Z)^2-(2分之一*X-三分之2Y-四分之三*Z)^2
会一T也行

1、25(X+Y)^2-16(X-Y)^2
= 25(X^2+2XY+Y^2)-16(X^2-2XY+Y^2)
=25X^2-16X^2+50XY+32XY+25Y^2-16Y^2
=9X^2-82XY+9Y^2
=(9X-Y)(X-9Y)
2、(X+Y)^2-14Y(X+Y)+49Y^2
=X^2+Y^2+2XY-14XY-14Y^2+49Y^2
=X^2-12XY+36Y^2
=(X-6Y)^2
3、没看清你写的是什么!
4、(二分之一*X+三分之二Y-四分之三Z)^2-(2分之一*X-三分之2Y-四分之三*Z)^2
=(X/2+2Y/3-3Z/4)^2-(X/2-2Y/3-3Z/4)^2
[把(X/2-3Z/4)提出来看作一项,就可以用（A+B）^2 = A^2+2AB+B^2了]
=[(X/2-3Z/4)+2Y/3]^2-[(X/2-3Z/4)-2Y/3]^2
=(X/2-3Z/4)^2+2(X/2-3Z/4)(2Y/3)+(2Y/3)^2-(X/2-3Z/4)^2+2(X/2-3Z/4)(2Y/3)-(2Y/3)^2
=4(X/2-3Z/4)(2Y/3)
=(2X-3Z)(2Y/3)

1、x(x-y)(x+y)-x(x+y)^2 1) (2x+5y)(2x-5y)(-4x^2-25y^2) 2) [（x+y)(x-y)-(x-y)^2+2y(x-y (1)(x^2/x)-y-x-y [(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y (x+y)^2-16(x-y)^2 (1)(x+y)^2-(x-y)^2 1、(x-2y)(x+y) x,y属于R*,且x+y=1,求证:(1)(x+1/x)(y+1/y)≥25/4 (2)(x+1/x)^2+(y+1/y 因式分解 (1)6(x-y)^3-3y(y-x)^2 (2)x(x-y)(a-b)-y(y-x)( 先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y -16(2x+y)^2+25(x-2y)^2 因式分解16(x+y)^2-25(x-y)^2