Answer:
supplementary
Explanation:
we have,
3x+15+2x=180
=> 5x +15 = 180
=> 5x = 180-15
=> 5x = 165
=> x = 165/5
=> x= 33
so, 3x+15 = 3*33+15
=> 99+15
=>114
2x = 2*33
=> 99
now we can check if these angles are supplementary
114 + 99 = 180
so, they are supplementary