Question

solve thissssssssssssssssssdd​

Answer 1

Answer:

1)

$({ {a}^{ - 1} + {b}^{ - 1 }) }^{ - 1} = a + b$

2)

$given \: (a + b) \: = 7 \: and \: ab \: = 10\\ \ on \: squring \: both \: side \: \\ \\ {a + b}^{2} = {7}^{2} \\ {a}^{2} + {b}^{2} + 2ab \: = 49 \: (by \: using \: ({a + b})^{2} \\ {a}^{2} + {b}^{2} + 2(10) = 49 \\ {a}^{2} + {b}^{2} = 49 - 10 \\ {a}^{2} + {b}^{2} = 39 \:$

3)