The constant shelling did not bother him as much as the loss of his food. As the siege wore on, fewer and fewer horses, mules, and dogs were seen wandering about Vicksburg. Shoe leather became a last resort of sustenance for many adults.
If the graph of a quadratic function has two x-intercepts, then the line of symmetry is the vertical line through the midpoint of the x-intercepts. The x-intercepts of the graph above are at -5 and 3. The line of symmetry goes through -1, which is the average of -5 and 3. (-5 + 3)/2 = -2/2 = -1.
The basic idea behind solving by graphing is that, since the solutions to ax2 + bx + c = 0 are the x-intercepts of y = ax2 + bx + c, you can look at the x-intercepts of the graph to find the solutions to the equation. There are difficulties with solving this way, though....