Question

if a+b=13 ,ab=42 find the value of a^2+b^2​

Answer 1

Answer:

let the value of a^2+b^2=x

using (a+b)^2 identity

a^2+b^2+2ab=x

a^2+b^2+2*42=x

a^2+b^2+84=x

a^2+b^2= -84