作业帮x+y=9, x-y=3 则2x^2- 2y^2的值是多少?要过程.
来源：学生作业帮助网 编辑：作业帮 时间：2024/07/19 14:51:19
x)ЮQЭ5Vx1Ө"HW2
{Xtɬ&ڿXbz6IE$h+Gҭ_`gC`Fn%քkWjj - nyx1cjb_\gu
lz(Ϧ|}5Oo= !=p8Hv%bV,Q
x+y=9, x-y=3 则2x^2- 2y^2的值是多少?要过程.
x+y=9, x-y=3 则2x^2- 2y^2的值是多少?
要过程.
x+y=9, x-y=3 则2x^2- 2y^2的值是多少?要过程.
2x^2- 2y^2
=2(x²-y²)
=2(x+y)(x-y)
=2×9×3
=54
2x^2- 2y^2
=2(x+y)(x-y)..............平方差公式
=2×9×3
=54
2x^2- 2y^2
=2（x^2-y^2）
=2(x+y)(x-y)
=2×9×3
=54
2x^2- 2y^2=2（x^2- y^2）=2（x+y）*（x-y）=2*9*3=54
x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2
3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9
4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
若2x=3y,则(x*x+y*y)/x*x=?
(x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)=
(x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
(x+y)(2x-3y)=?
若2x+3y=2004,则代数式2(3x-2y)-(x-y)+(-x+9y)=...
若2x+y=2012,则代数式2(3x-2y)-(x-y)+(-x+9y)=
x+y=9 x-y=3则2x²-2y²=
已知x-2y=3,则(2x+y-6)/(3x-y-9)=?
3^x+2x=y,x
9y=3x-(x-1),4(x+y)-(2x+4)=8y
5x=3y,(2x+y)的平方=5x(x+y)+9
已知2x=3y,则y分之x=< >,y分之x+y=< >.
若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值