Question

Simplify ( 5 √3 − √7 ) × (5 √3 + √7 ) :

Answer 1

68

Step-by-step explanation:

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

so,

(5√3)^2-(√7)^2

= 25×3-7

=75-7

=68

Answer 2

$\displaystyle\huge\red{\underline{\underline{Solution}}}$

FORMULA TO BE IMPLEMENTED

We are aware of the identity that

$\pink { {a}^{2} - {b}^{2} =( a + b)(a - b)}$

TO EVALUATE

$( 5\sqrt{3} - \sqrt{7} )(5 \sqrt{3} + \sqrt{7} )$

EVALUATION

$( 5\sqrt{3} - \sqrt{7} )(5 \sqrt{3} + \sqrt{7} )$

$= {(5 \sqrt{3} )} \: ^{2} - ( { \sqrt{7}) } \: ^{2} \: \: using \: above \: mentioned \: identity$

$= 75 - 7$

$= 68$

RESULT

$\red {\fbox{THE ANSWER IS \: \: 68}}$