Answer:
- The arcs on the Golden Gate Bridge.
Explanation:
I think about the Golden Gate Bridge, which is a suspension bridge.
As in any suspension bridge, a long cable is supported by two large supports.
The cable falls from a support, in the form of a curve concave upwards, to a minimum point that is the vertex of the<em> parabola</em>, through which the axis of <em>symmetry</em> passes, and curves again upwards to ascend to the upper end of the other support.
As a <em>unique feature</em> of this parabolic arc you can tell that the the concavity is upward; the parabola open upward.
Also, you can tell that the parabola is vertical, which means that the axis of symmetry is vertical.
The <em>symmetry</em> is clear because to the curve to the left of the vertex is a mirror image of the curve to the right of the vertex.
Consider expression 
First, you can factor it:
Since x is integer number, then you can see that x-1 is previous integer number (x-1 is 1 unit smaller than x).
Therefore, x-1 and x are two consecutive integers. When you have two consecutive integers, one of them is always even and one is always odd. Multiplying even integer number by odd integer number you always get even integer number.
Thus, 
is always even.
The answer is 1.2 b/c you have to solve x by simplifying both sides of the equation and isolating the variable.
