Question

If a−b=13 and ab=28 then a2+b2=?

Answer 1

Answer:

a-b=13

squaring both sides

(a-b)2=(13)2. (a-b)2=A2+b2-2ab

a2+b2-2ab=(13)2

a2+b2-2*28=(13)2

a2+b2-56=169

a2+b2=169+56

a2+b2=225