Hello i need help with this differential equations system!

x,u and l are functions of t... so u(t), x(t) and l(t)

tf is free.

Could you find the solutions?

$\displaystyle

\frac{dx}{dt}=-x+u

$

$\displaystyle

\frac{dl}{dt}=l

$

$\displaystyle

l -2u-2=0

$

boundary conditions

x(0)=1

x(tf)=0

l(tf)=2