Question

A+b = 8 , a× b = 10 then how much is a ?

Answer 1

Oneway

$a + b = 8 \: \: \: \: (1) \\ and \\ a \times b = 10 \: \: \: \: (2)$

From (1)

$b = 8 - a \: \: \: \: (3)$

From (2) and (3)

$a \times (8 - a) = 10 \\ 8a - {a}^{2} = 10 \\ {a}^{2} - 8a + 10 = 0$

On Solving this you get

$a = 4 + \sqrt{6} \: and \: 4 - \sqrt{6}$