You have the following points:
J(2,-1), K(4,-5), L(3,1)
To reflect the previous points around the line x = -1, consider the horizontal distance of each point to the given line x=-1. The reflected point is obtained by using the same distance to the line but in the other side.
You proceed as follow:
J(2,-1)
the distance of the previous point to the line x=-1 is 2-(-1) = 3. You subtract this value to x = -1. Thus, the x-coordinate of the new point is:
-1-3 = -4
and the new point is:
J(2,-1) => J'(-4,-1)
For K(4,-5) you have:
distance to the line x=-1 is 4-(-1) = 5. Subtract this value to the line.
-1-5 = -6
and the new point is:
K(4,-5) => K'(-6,-5)
For L(3,1):
distance to the line x=-1 is 3-(-1) = 4.
-1-4 = -5
and the new point is:
L(3,1) => L'(-5,1)
A plot of the original and reflected points is given below:
where the figure with black lines is the original figure and the figure with blue lines is the reflected one.
