Question

plz answer this question

Answer 1

using identity (A-B)(A+B)=A²-B² we get,
= (2/b)² - (5/c)²
= 4/b² - 25/c²

Answer 2

Hey!!

In this question if we notice,

The identity of (a+b) (a-b) = a2 -b2

So here,

a= 2/b and b= 5/c

Hence, a^2 - b^2

2/b^2- 5/c^2

= 4b^2- 25c^4

Thanks..if any doubts u can comment :)