Using the digits 1 to 9 at most one time each, fill in the boxes to make the equality true:
(_+_-_+_)-(_+_-_+_)=0

Determine whether angle-angle-angle (aaa) is a valid means for establishing triangle congruence. if it is a valid criterion, explain why. if it is not valid, use geogebra to create a counterexample demonstrating that it doesn’t work and give an explanation. if you construct a counterexample, take a screenshot of your work, save it, and insert the image in the space below.