Answer:
2x + 3 + 3x +12 + 90 = 180 (degree )
5x +105=180 (degree )
5x= 180-105 (degree )
5x = 75 (degree )
x = 75/5 (degree )
x = 15 #
therefore, 2x + 3= 2*15 + 3
=30+3
= 33#
3x + 12 = 3*15+12
= 45 +12
= 57#