Calculate Polynomial Expression at x = -2

Consider the polynomial function defined by the expression:

$$P(x) = 3x^4 - 8x^3 + 6x^2 - 4x + 5$$

We want to find the value of $P(-2)$ and subsequently $P(-2)$ divided by $-4$ in decimal form.

Calculate $P(-2)$ and enter the solution as a grid-in response.