[tex]\textbf {The answer is h = -2/9.}[/tex]
[tex]\textrm {We are given that 9/2h = -1. Hence, divide by 9/2 on both sides.}[/tex]
[tex]\frac{9/2h}{9/2} = \frac{-1}{9/2}[/tex]
[tex]\boxed {h = -\frac{2}{9}}[/tex]