Question

If a + b = 5 and a - b = 1 find the value of a² + b²/2ab

Answer 1

a+b=5

a-b=1

By adding the above two equations , we get a=3 ,

When we substitute a=3 , in one of the equations we get b=2

a=3 and b=2

a² + b²=9+4

=13

2ab =2*3*2

=12

so

a² + b²/2ab=13/12