Question

bài 4:

a) (x+y)²+(x-y)²-2x²

b) 2(x-y)(x+y)+(x+y)²+(x-y)²

c) (x-3)(x+3)-(x-5)²

Answer 1

các bn ơi giúp mình với 

Answer 2

a.2y²  

b) =(2x)²=4x²

c chua biet

 

Answer 3

a) \(=x^2+2xy+y^2+x^2-2xy+y^2-2x^2=2y^2\)

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

c) \(=x^2-9-x^2+10x-25=10x-34\)

 

Answer 4

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

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

c) \(\left(x-3\right)\left(x+3\right)-\left(x-5\right)^2=\left(x^2-9\right)-\left(x^2-10x+25\right)=x^2-9-x^2+10x-25=10x-34\)