Question

A+b=11 and ab=30 find a^2+b^2

Answer 1

A+B=11

therefore,

(A+B)^2=121

A2+B2+2AB=121

therefore,

A2+B2+60=121

therefore,

A2+B2=61

Answer 2

a=11-b

a=30/b

comparing above

11b-b^2=30

b^2-11b+30=0

b^2-6b-5b+30=0

b(b-6)-5(b-6)=0

(b-6)(b-5)=0

either,,,

b=6

or

b=5

when b=5

a=6

when b=6

a=5

now for a=6, b=5

6^2+5^2=61