See explanation below
Step-by-step explanation:
The coordinates of triangle RST: R(7,4), S(5,-3), and T(2,6)
A reflection across the y = x means (x, y) becomes (y, x)
Plotting the graph of the original image:
After the reflection aross the line y = x, the new coordiantes will be:
R'(4, 7), S(-3, 5) and (T(6, 2)
plotting the graph of the image:
Both the original and new image: