For the first one.....here's a hint......expand each answer.....see if the second one leads you to
y = x^2 + 4x - 3
For the second one.....I'll use a graph [ although I can also solve it algebraically, if you want me to ]
Look at the graph, here.....
The height of the arch is ≈ 381 ft and the length of the bridge above the arch is ≈ 1791 ft