Question

Tính :

a) \(\left(x+2y\right)^2\)

b) \(\left(x-3y\right)\left(x+3y\right)\)

c) \(\left(5-x\right)^2\)

Answer 1

a) (x+2y)²=x²+4xy+4y²

b) (x-3y)(x+3y)=x²-9y²

c) (5-x)²=25-10x+x²

Answer 2

a) (x + 2y)² = x² + 4xy + 4y²

b) (x - 3y) (x + 3y) = x² - 9y²

c) (5 - x)² = 25 - 10x + x²

Answer 3

a) ( x + 2y )²
= x² + 2. x . 2y + ( 2y )²
= x² + 4xy + 4y²
b) ( x - 3y ) ( x + 3y )
= x² - ( 3y )²
= x² - 9y²
c) ( 5 - x )²
= 5² - 2 . 5. x + x²
= 25 - 10x + x²

Answer 4

a) x² + 4y +4y²

b) x² - 9y²

c) 25 - 10x + x²