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Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

Which radical expression is a rational number? a. √ 360 b. √ 644 c. √ 225 d. √ 122

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.