Two angles are called supplementary angles if the sum of two angles is 180 degrees and they form a linear pair.
Here we are given than angle P and angle Q are supplementary angles.
Sum of angle P and angle Q will be 180.
Angle P measures 5x and angle Q measures 3x – 12
Adding the two angles,
[tex]5x+(3x-12) =180[/tex]
[tex]8x-12=180[/tex]
[tex]8x=180+12[/tex]
[tex]8x=192[/tex]
x=24
Angle P = 5x
Angle P =5*24 =120
Answer: Angle P is 120 degrees.