Suppose the $f(x,y)$ is a smooth function and that its partial derivatives have the values, $f_x(-6, 1) = -3$ and $f_y(-6, 1) = 3$. Given that $f(-6, 1) = 0$, use this information to estimate the value of $f(-5, 2)$. Note this is analogous to finding the tangent line approximation to a function of one variable. In fancy terms, it is the first Taylor approximation. Estimate of (integer value) $f(-5, 2)$