Given lines are: 2x – by + 5 = 0 and ax + 3y = 2

If two lines to be parallel then their slopes must be equal.

In equation 2x – by + 5 = 0,

by = 2x + 5

y = (2/b) x + 5/b

So, the slope of the line (m₁) = 2/b

And in equation ax + 3y = 2,

3y = -ax + 2

y = (-a/3) x + 2/3

So, the slope of the line (m₂) = (-a/3)

As the lines are parallel

m₁ = m₂

2/b = -a/3

6 = -ab

Hence, the relation connecting a and b is ab + 6 = 0