If angle t is a right angle what is the hypothesis and corresponding reason

In the coordinate plan (-6,9) b (3,9) c (3,3) def is shown in the coordinate plan below

Select the correct answer from the drop-down menu. subtracting 3xy^2 from 8xy^2 gives the same result as the expression. [tex]3xy ^{2} - 8xy ^{2} [/tex][tex] { - 7xy}^{2} - {2xy}^{2} [/tex][tex] {7xy}^{2} - {2xy}^{2} [/tex]

Solve the given system of equations. 2y= -x+9 , 3x-6= -15