Detail solution
Let's take the limit
$$\lim_{x \to 0^+} \left(1 - 4 x\right)^{\frac{1}{x}}$$
transform
do replacement
$$u = \frac{1}{\left(-4\right) x}$$
then
$$\lim_{x \to 0^+} \left(1 - \frac{4}{\frac{1}{x}}\right)^{\frac{1}{x}}$$ =
=
$$\lim_{u \to 0^+} \left(1 + \frac{1}{u}\right)^{- 4 u}$$
=
$$\lim_{u \to 0^+} \left(1 + \frac{1}{u}\right)^{- 4 u}$$
=
$$\left(\left(\lim_{u \to 0^+} \left(1 + \frac{1}{u}\right)^{u}\right)\right)^{-4}$$
The limit
$$\lim_{u \to 0^+} \left(1 + \frac{1}{u}\right)^{u}$$
is second remarkable limit, is equal to e ~ 2.718281828459045
then
$$\left(\left(\lim_{u \to 0^+} \left(1 + \frac{1}{u}\right)^{u}\right)\right)^{-4} = e^{-4}$$
The final answer:
$$\lim_{x \to 0^+} \left(1 - 4 x\right)^{\frac{1}{x}} = e^{-4}$$
Lopital's rule
There is no sense to apply Lopital's rule to this function since there is no indeterminateness of 0/0 or oo/oo type
x _________
lim \/ 1 - 4*x
x->0+
$$\lim_{x \to 0^+} \left(1 - 4 x\right)^{\frac{1}{x}}$$
$$e^{-4}$$
x _________
lim \/ 1 - 4*x
x->0-
$$\lim_{x \to 0^-} \left(1 - 4 x\right)^{\frac{1}{x}}$$
$$e^{-4}$$