If l is a line of symmetry, plot the partner points for the ones shown."

Answer:
Points will be A'(5, -4), B'(4, -2), C'(1, 3), D'(2, 1).
Step-by-step explanation:
Line of symmetry means image of the points on one side will be equidistant on the other side of the line. In other words points on one side will create a mirror image about the line of symmetry.
Now in the graph points given are A(1, -4), B(2, -2), C(5, 3) and D(4, 1)
We have to plot the partner points of the points given about the line of symmetry l.
These points will be A'(1+4, -4), B'(2+2, -2), C'(5-4, 3), D'(4-2, 1)
Or A'(5, -4), B'(4, -2), C'(1, 3) and D'(2, 1)