Root of Polynomial Expression

Consider the polynomial function defined by the expression $p(x) = 2x^4 - 3x^3 + 5x^2 - x + 4$. If this polynomial is factored as $p(x) = (x - r)(2x^3 + ax^2 + bx + c)$ where $r$ is a root of the polynomial, determine the value of $r$. Your answer should be submitted in the grid-in section and should be expressed as a decimal.