Well with those sorts of things, there are online tools you can use. I used one from the explore learning website
Pick the rotate around origin operation, simplify the -80 to a -16 and the 45 to a 9, then take those values and place your point on the graph. Adjust the rotation tool to 90 degrees, and your new point should be on -9, -16. Multiply both numbers by 5 and your answer would be -45, -80.
