Question

Tentukan hasil perkalian berikut ini!
a. (2a+b) x (2a+b)
b. (x-2y) - (x+2y)

Jawab secepatnya ya!

Answer 1

A. (2a + b) x (2a + b) = 5a^2 + 2ab + 2ab + b^2 = 5a^2 + 4ab + b^2  
    = 2a x 2a = 4a^2
    = 2a x b = 2ab
    = b x 2a = 2ab
    = b x b = b^2
b. (x - 2y) - (x + 2y) = -x^2 + 2xy + 2xy - 4y^2 = -x^2 + 4xy - 4y^2
    = x x (-x) = -x^2
    = x x 2y = 2xy
    = (-2y) x (-x) = 2xy
    = -2y x 2y = -4y^2