a) 2(x-y)(x+y)+(x+y)^2+(x-y)^2 b) (x-y+z)^2+(z-y)^2+2(x-y+z)(y-z) 08/07/2021 Bởi Ximena a) 2(x-y)(x+y)+(x+y)^2+(x-y)^2 b) (x-y+z)^2+(z-y)^2+2(x-y+z)(y-z)
a) `2(x-y)(x+y)+(x+y)²+(x-y)²` `= (x+y+x-y)²` `= (2x)²=4x²` b) `(x-y-z)²+(z-y)²+2(x-y+z)(y-z)` `= (x-y-z+z-y)²` `= (x-2y)²` Bình luận
`a) 2(x-y)(x+y)+(x+y)^2+(x-y)^2` `=2(x^2-y^2)+x^2+2xy+y^2+x^2-2xy+y^2` `=2x^2-2y^2+x^2+y^2+x^2+y^2` `=4x^2` `b) (x-y+z)^2+(z-y)^2+2(x-y+z)(y-z)` `=(x-y+z)^2+2(x-y+z)(y-z)+(z-y)^2` `=(x-y+z).(x-y+z+2y-2z)+(z-y)^2` `=(x-y+z)(x+y-z)+(z-y)^2` `=[x+(z-y)].[x-(z-y)]+(z-y)^2` `=x^2-(z-y)^2+(z-y)^2` `=x^2` Bình luận
a) `2(x-y)(x+y)+(x+y)²+(x-y)²`
`= (x+y+x-y)²`
`= (2x)²=4x²`
b) `(x-y-z)²+(z-y)²+2(x-y+z)(y-z)`
`= (x-y-z+z-y)²`
`= (x-2y)²`
`a) 2(x-y)(x+y)+(x+y)^2+(x-y)^2`
`=2(x^2-y^2)+x^2+2xy+y^2+x^2-2xy+y^2`
`=2x^2-2y^2+x^2+y^2+x^2+y^2`
`=4x^2`
`b) (x-y+z)^2+(z-y)^2+2(x-y+z)(y-z)`
`=(x-y+z)^2+2(x-y+z)(y-z)+(z-y)^2`
`=(x-y+z).(x-y+z+2y-2z)+(z-y)^2`
`=(x-y+z)(x+y-z)+(z-y)^2`
`=[x+(z-y)].[x-(z-y)]+(z-y)^2`
`=x^2-(z-y)^2+(z-y)^2`
`=x^2`