Question

rút gọn biểu thức

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)

ahuhu giúp mk với

Answer 1

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

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

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

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

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

Answer 2

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

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

Answer 3