Question

if a^r+b^r=51 ,ab= -1 ,find (a+b)

Answer 1

If the question is

a^2 +b^2 = 51

and ab = -1 , (a+b)^2 =?

then , (a+b) ^2 = a^2+b^2 +2ab

= 51 + 2(-1)

= 49

And now if you have to find just (a + b )

then (a+b) ^2 = 49

(a+b) = √ 49

= 7

therefore a+b = 7