Question

show that (4x+7y)2-(4x-7y)2=112xy

Answer 1

LHS :
( 4x+7y)'2-(4x-7y)'2. =16x'2+49y'2+56xy-[16x'2+49y'2-56xy]
=16x'2+49y'2+56xy-16x'2-49y'2+56xy
=56xy+56xy
=112xy
=RHS

NOTE: ' means power

Answer 2

Answer & Step-by-step explanation:

(4x + 7y)^2- (4x - 7y)^2 = 112xy

LHS equation =  ( 4x+7y)^2 - (4x-7y)^2 = 16$x^{2}$ + 49$y^{2}$ + 56xy - (16$x^{2}$ + 49$y^{2}$- 56xy)

= 16$x^{2}$ + 49$y^{2}$ + 56xy - 16$x^{2}$ - 49$y^{2}$ + 56xy

= 56xy  +56xy

= 112xy  = RHS equation

Though some random person has answered first i took time to insert the correct $x^{2}$ and $y^{2}$, so mark me the brainiest.