Question

Please answer fast..needed urgently...will mark as brainliest..​

Answer 1

$\tt \sqrt{13-a\sqrt{10}} = \sqrt{8} + \sqrt{5} \\ \\ \tt Squaring\:both\:sides \\ \\ \tt \therefore 13 - a\sqrt{10} = {( \sqrt{8} + \sqrt{5})}^{2} \\ \\ \tt \therefore 13 - a\sqrt{10} = {\sqrt{8}}^{2} + {\sqrt{5}}^{2} + 2(\sqrt{8})(\sqrt{5}) \\ \\ \tt \therefore 13 - a\sqrt{10} = 8 + 5 + 2\sqrt{40} \\ \\ \tt \therefore \cancel{13} - a\sqrt{10} = \cancel{13} + 4\sqrt{10} \\ \\ \tt \therefore \boxed{\bold{\underline{\red{ \tt a = -4 }}}}$

Answer 2

$\huge\fbox \red{✔AN} {\colorbox{crimson}{SW}}\fbox\red{ER✔}$

=> 13-a√10=(√8+√5)²= 8+5+2√40= 13+4√10

=> 13-a√10= 13+4√10

=> -a√10= 4√10

=> -a=4

So,

=> a = -4

So on comparing,

=> a = - 4.

• I Hope it's Helpful My Friend.