t_{2} = \frac{l - u t_{1}}{v} = \frac{l - u l / (v + u)}{v} = \frac{v l + u l - u l}{v (v + u)} = \frac{l}{v + u} = t_{1}

${t_2 = \frac{l-ut_1}{v} = \frac{l-ul/(v+u)}{v} = \frac{vl+ul-ul}{v(v+u)} = \frac{l}{v+u} = t_1}$

Error