In order to find the equation of each line, we can use two points of each line in the slope-intercept form of the linear equation:
[tex]y=mx+b[/tex]
For the crescent line, let's use the points (0, 4) and (8, 10), so we have:
[tex]\begin{gathered} y=mx+b \\ (0,4)\colon \\ 4=0\cdot m+b \\ b=4 \\ \\ (8,10)\colon \\ 10=8m+4 \\ 8m=6 \\ m=\frac{3}{4} \end{gathered}[/tex]
So the equation is y = 3/4x + 4.
For the second line, let's use the points (0, 18) and (8, 10):
[tex]\begin{gathered} y=mx+b \\ (0,18)\colon \\ 18=0m+b \\ b=18 \\ \\ (8,10)\colon \\ 10=8m+18 \\ 8m=-8 \\ m=-1 \end{gathered}[/tex]
So this equation is y = -x + 18.
Therefore the correct option is D.
