Question

$(a-b)=8,ab=4.25$
$(a+b)=$?

Answer 1

We have,

$a-b=8$ and $ab=4.25$

We know that

$(a+b{)}^2=(a-b{)}^2+4ab$

$(a+b{)}^2=8^2+4\times 4.25$

$(a+b{)}^2=64+17$

$(a+b{)}^2=81$

$a+b=\pm 9$

Hence, this is the answer.