Let's begin by listing out the information given to us:
Left side: y = 2x + 8
Center of the bridge: (0, 2)
[tex]\begin{gathered} y=2x+8 \\ m=2 \\ \text{However, the bridge is perpendicular to }y=2x+8\colon \\ m(perpendicular)=-\frac{1}{m} \\ m(perpendicular)=-\frac{1}{2} \end{gathered}[/tex]Use the point-slope formula to get the equation of the bridge:
[tex]\begin{gathered} y-y_1=m(x-x_1) \\ (x_1,y_1)=(0,2);m=m(perpendicular)=-\frac{1}{2} \\ y-2=-\frac{1}{2}(x-0) \\ y-2=-\frac{1}{2}x \\ y=-\frac{1}{2}x+2 \\ \\ \therefore\text{ equation of the line representing the bridge is }y=-\frac{1}{2}x+2 \end{gathered}[/tex]