[tex]5 {h}^{2} - 5h - 15 = 0 \\ 5 {h}^{2} - 5h = 15 \\ \frac{5 {h}^{2} - 5h}{5} = \frac{15}{5} \\ {h}^{2} - h = 3 \\ {h}^{2} - h + \frac{1}{4} = 3 + \frac{1}{4} \\ {(h - \frac{1}{2}) }^{2} = \frac{13}{4} \\ h - \frac{1}{2} =±\frac{\sqrt{13}}{2} \\ h = ±\frac{\sqrt{13}}{2} + \frac{1}{2}[/tex]