Question

solve it please by using formulas ​

Answer 1

Answer:

Step-by-step explanation:

Answer 2

Answer:

$\frac{1}{25 {r}^{2} } - \frac{1}{49 {s}^{2} }$

Step-by-step explanation:

Using the identity :

(a+b)(a-b) = a^2-b^2

= 1/25r^2 - 1/49s^2