Science and Mathematics for Engineering 6th Edition by John Bird

Exercise 15

In an engineering process two variables $x$ and $y$ are related by the equation: $y = a x + \frac { b } { x }$ where ' $a$ ' and ' $b$ ' are constants. Evaluate ' $a$ ' and ' $b$ ' if $y = 15$ when $x = 1$ and $y = 13$ when
$$x = 3$$