Question

[I like you]

Rút gọn:

a,(x+2)^2-(x-2)^2-2(x-2)(x+2)

b,(x+y)^2+(x+y)^2+2(x-y)(x+y)

c,(x-y+z)^2-2(x+y)-2(x+y)(x-y)-z^2

Nhanh giúp mk nha ,mơn

Answer 1

[Phạm Thị Thùy Linh]

\(a,\left(x+2\right)^2-\left(x-2\right)^2-2\left(x-2\right)\left(x+2\right).\)

\(=\left(x+2-x+2\right)^2=4^2=16\)

\(b,\left(x-y\right)^2+\left(x+y\right)^2+2\left(x-y\right)\left(x+y\right)\)

\(=\left(x-y+x+y\right)^2=x^2\)

\(c,\left(x-y+z\right)^2-2\left(x+y\right)-2\left(x+y\right)\left(x-y\right)-z^2\)