$(a+2b)^2 -(a -2b)^2$ is equal to :
Answer & explanation
Correct answer: option 3
(x + y)2 = x2 + y2 + 2xy
(x - y)2 = x2 + y2 - 2xy
(a + 2b)2 - (a - 2b)2
= a2 + 4b2 + 4ab - (a2 + 4b2 - 4ab)
= a2 + 4b2 + 4ab - a2 - 4b2 + 4ab
= 8ab
$(a+2b)^2 -(a -2b)^2$ is equal to :
Correct answer: option 3
(x + y)2 = x2 + y2 + 2xy
(x - y)2 = x2 + y2 - 2xy
(a + 2b)2 - (a - 2b)2
= a2 + 4b2 + 4ab - (a2 + 4b2 - 4ab)
= a2 + 4b2 + 4ab - a2 - 4b2 + 4ab
= 8ab