hello
to find the slope of the line CD, let's use the formula of slope
[tex]\begin{gathered} \text{slope}=\frac{y_2-y_1}{x_2-x_1} \\ y_2=13 \\ x_2=5 \\ y_1=-7 \\ x_1=1 \end{gathered}[/tex]now we can simple input the values and solve for slope (m)
[tex]\begin{gathered} m=\frac{y_2-y_1}{x_2-x_1} \\ m=\frac{13-(-7)}{5-1} \\ m=\frac{20}{4} \\ m=5 \end{gathered}[/tex]from the calculation above, the slope of the line CD is equal to 5
