Question

a) (2x - y )² + ( 2x+y )² = ? 

b) (5x - 3y) (5x+3y)-2(2x+3y)³ - 12xy = ? 

c) (x - 3 )²+ (2x+1)²-2 (x-2)(2x+1) =?

d) (x-3)² - (3x +1 )² =?

xin hãy giúp mình với >_<

Answer 1

a,(2x-y)²+(2x+y)²=(2x²-2*2xy+y²)+(2x²+2*2xy+y²)

                            =2x²-4xy+y²+2x²+4xy+y²

                            =4x²+2y²

Answer 2

a) (2x-y)+(2x+y)=(2x/2-2*2xy+y/2)+(2x/2 +2*2xy+y/2)

=2x/2-4xy+y/2+2x/2+4xy+y/2

=4xy/2+2y2

Answer 3

\(a) ( 4x^2 - 4xy + y^2 ) + ( 4x^2 + 4xy + y^2 ) = 8x^2 + 2y^2 \)