Question

Q8] Using the identity simplify the following:-
i)
ii)
(2x + 5)2 - (2x - 5)2
6x2 - 5y)?​

Answer 1

Answer:

(2x + 5)2 - (2x - 5)2 = [(2x)2 + 2(2x)(5) + (5)2] - [(2x)2 - 2(2x)(5) + (5)2]

= [4x2 + 20x + 25] - [4x2 - 20x + 25]

= 4x2 + 20x + 25 - 4x2 + 20x - 25

= (4x2 - 4x2 ) + (20x + 20x) + (25 - 25)

= 0 + 40x + 0

= 40x

Step-by-step explanation:

(2x + 5)2 - (2x - 5)2 = [(2x)2 + 2(2x)(5) + (5)2] - [(2x)2 - 2(2x)(5) + (5)2]

= [4x2 + 20x + 25] - [4x2 - 20x + 25]

= 4x2 + 20x + 25 - 4x2 + 20x - 25

= (4x2 - 4x2 ) + (20x + 20x) + (25 - 25)

= 0 + 40x + 0

= 40x