[填空题]
Consider the functiofhg ch7( +ujp;h7ps qcj/ nv-oe*b5y; n9x5( 1ly6g1vhs k offa $ f(x)=\frac{4 x^{2}+p x}{x+1}$ , where $x \neq-1$ and $p \in \mathbb{R}$ .
Find the value of p for which the graph of f has exactly one point with a gradient of zero.