The simplified form of $(7x + 4y)^2 +(7x−4y)^2$ is:
Answer & explanation
Correct answer: option 1
( a + b)2 = a2 + b2 + 2ab
( a - b)2 = a2+ b2 - 2ab
( 7x + 4y)2 + (7x - 4y)2 = 49x2 + 16y2 + 56xy + 49x2 +16y2 - 56xy
(7x + 4y)2 + ( 7x - 4y)2 = 98x2 + 32y