Question

a) ( x+y )² + ( x-y )² -2 ( x+y ) ( x-y )

b) ( x+2 ) ( x² - 2x + 4 ) + ( 1 - x ) (1 + x + x² )

Answer 1

a)

Answer 2

a,(x+y-x-y)²=(-2y)²=4y²

b,\(x^3+8+1-x^3=9\)

Answer 3

a

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

Answer 4

b)

\(\left(x+2\right)\left(x^2-2x+4\right)+\left(1-x\right)\left(1+x+x^2\right)\)

\(=x^3+2^3+1^3-x^3=9\)