Respuesta:
[tex]u=\frac{4}{5}[/tex]
Explicación paso a paso:
[tex]5u^2-4u=0\\\\\\u_{1,\:2}=\frac{-\left(-4\right)\pm \sqrt{\left(-4\right)^2-4\cdot \:5\cdot \:0}}{2\cdot \:5}\\\\\\u_{1,\:2}=\frac{-\left(-4\right)\pm \:4}{2\cdot \:5}\\\\\\u_1=\frac{-\left(-4\right)+4}{2\cdot \:5}\\\\\\u=\frac{4}{5}[/tex]
