Answer
$\dfrac{1}{(s-1)^2}$
Work Step by Step
The Laplace Transform can be written as:
$L[F(t)]=\int_{0}^{\infty} e^{-st} f(t) dt $
We are given that $f(t)=te^t$
Now, $L[F(t)]=\int_{0}^{\infty} e^{-st} f(t) dt \\=\int_{0}^{\infty} e^{-st} [te^t] \ dt\\=\dfrac{1}{(s-1)^2} $