Question

If $a^2+b^2=41$ and $ab=4$, find: $a+b$

Answer 1

We have,

$a^2+b^2=41$ and $ab=4$

We know that

$(a+b{)}^2=a^2+b^2+2ab$

$(a+b{)}^2=41+2\times 4$

$(a+b{)}^2=41+8$

$(a+b{)}^2=49$

$a+b=\pm 7$

Hence, this is the answer.