Solve for x,y, and z

Answer:Step-by-step explanation:8x + 13y + 7 = 180     {Linear pair}8x + 13y = 180 - 78x + 13y =173         -------------------(I)9x - 7 + 13y + 7 = 180        {linear pair}9x + 13y = 180 ----------------(II)Multiply equation by (-1) and then add with equation (II). And thus y will be eliminated.(I)* (-1)           -8x - 13y = -173(II)                 9x + 13y = 180    {Now add}                       x           =  7 Plug in x = 7 in equation (I)8*7 + 13y = 17356   + 13y = 173          13y = 173 - 56          13y = 117            y = 117/13           y = 95y - 11 + z + 8x = 180    {Straight line angles}5*9 - 11 + z + 8*7 = 18045 - 11 + z + 56   = 180             z + 90    = 180                        z = 180 - 90z = 90