The support for a window air conditioning unit forms a triangle and an exterior angle. What is the measure

Answer:
Step-by-step explanation:
We know that the sum of all internal angles of a triangle must sum 180, that is
[tex](5x-6)+3x+90=180\\8x=180-84\\x=\frac{96}{8}\\ x=12[/tex]
By sum of angle, we know that the exterior angle and the adjacent interior angle must sum 180, because they are on a straight angle
[tex]y+5x-6=180[/tex]
But, [tex]x=12[/tex]
So,
[tex]y+5(12)-6=180\\y+60-6=180\\y=180-54\\y=126\°[/tex]
Therefore, the exterior angle measures 126°.