Question

pls ans tomorrow exam is there​

Answer 1

Answer:

Required values of a and b are 0 and 2 respectively.

Step-by-step explanation:

$\implies \dfrac{ \sqrt{7} + \sqrt{5} }{ \sqrt{7} - \sqrt{5} } - \dfrac{ \sqrt{7} - \sqrt{5} }{ \sqrt{7} + \sqrt{5} } \\ \\ \\ \implies \dfrac{( \sqrt{7} + \sqrt{ 5}) {}^{2} - ( \sqrt{7} - \sqrt{5} ) {}^{2} }{ ( \sqrt{7} + \sqrt{ 5}) {}^{} ( \sqrt{7} - \sqrt{5} )}$

Using :

• ( a + b )^2 - ( a - b )^2 = 4ab
• ( a + b )( a - b ) = a^2 - b^2

Denominator :

• 4√7.√5 = 4√35

Nominator :

• ( √7 )^2 - ( √5 )^2 = 7 - 5 = 2

$\implies \dfrac{4 \sqrt{35} }{2 }$

= > 2√35

= > 0 + 2√35

Given expression is equal to a + √35b

= > Rational number of LHS = Rational number on RHS

= > 0 = a

= > Irritation number of LHS = Irrational number on RHS

= > √35 b = 2√35

= > b = 2

Hence the required values of a and b are 0 and 2 respectively.

Answer 2

Step-by-step explanation:

hope it helps........