Question

if a_b =7 and ab=9 then a^(2)+b^(2)=?

Answer 1

a-b =7
ab = 9
-----------------

(a-b) =7

Square on both sides,
(a-b)² =7²

a²+b²-2ab =49

a²+b² -2(9) =49

a²+b² = 49+2(9)

a²+b² =49+18

a²+b² = 67



I hope this will help you


-by ABHAY

Answer 2

$a - b = 7 \: \: and \: \: ab = 9 \\ \\ a^{2} + b^{2} \\ = (a - b)^{2} + 2ab \\ = (7)^{2} - 2 \times 9 \\ = 49 + 18 \\ = 67 \: \: (ans.)$

Hope it will help you .