Given the following system of equations use the inverse of a matrix to solve for the values of x and y and give your answer as an ordered pair

Pls! does anybody know a shortcut for answering these types of questions in the future?

1) in triangle the, what is the measure of angle t (in degrees)? 2) in triangle bat, the measure of angle b is 66∘, and the measure of angle t is 77∘.what is the measure of the exterior angle at a (in degrees)?

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39