Hi there!
![\large\boxed{2, -9}](https://img.qammunity.org/2022/formulas/mathematics/high-school/hbyl57uatjcb0s2z805g8v82ffxgcs5d5t.png)
We can create an equation for the line PR using the given coordinates. Use the following formula for the slope:
![m = (y_2-y_1)/(x_2-x_1)](https://img.qammunity.org/2022/formulas/mathematics/high-school/5mdnic5ea8xo5rpzqfaeycvir8wo0wcfri.png)
Plug in the coordinates for P and R:
![m = (-5-(-1))/(-1-(-4)) = -(4)/(3)](https://img.qammunity.org/2022/formulas/mathematics/high-school/i6zg44jefd7nj2r1vc0llxkmd3242uhkpy.png)
Find the equation by using point-slope form:
y - y1 = m(x - x1)
Plug in a coordinate and the slope:
y - (-5) = -4/3(x - ( - 1))
Simplify:
y + 5 = -4/3(x + 1)
To find the y-coordinate if x = 2, plug in the x value:
y + 5 = -4/3(2 + 1)
y + 5 = -4/3(3)
y + 5 = -4
y = -9
Thus, the coordinate is (2, -9)