Question

plz solve it this question by evaluate it

Answer 1

We know
(x + y)2 = x2 + 2xy + y2 (1)
(x - y)2 = x2 - 2xy + y2 (2)
By subtracting (2) from (1)
(x + y)2 - (x - y)2 = x2 + 2xy + y2 - x2 + 2xy - y2
(x + y)2 - (x - y)2 = 4xy (3)
Using this identity in these questions

i.) Here x = a/2b , y = 2b/a
By (3),
(a/2b + 2b/a)2 - (a/2b - 2b/a)2= 4*(a/2b)*(2b/a)
(a/2b + 2b/a)2 - (a/2b - 2b/a)2= 4
(a/2b + 2b/a)2 - (a/2b - 2b/a)2- 4 =0
So, answer is 0.

ii.)Here x = 4a , y = 3b
By (3),
(4a + 3b)2 - (4a - 3b)2= 4*(4a)*(3b)
(4a + 3b)2 - (4a - 3b)2= 48ab
(4a + 3b)2 - (4a - 3b)2+ 48ab = 96ab
So, answer is 96ab.