Answer:
<ABC = 49°
Step-by-step explanation:
The sum of two supplementary angle is 180. From the diagram, the two angles are 3x+4 and 8x+11. IF this two angles are supplementary then;
3x+4+8x+11 = 180
11x+15= 180
11x = 180-15
11x = 165
x = 165/11
x = 15
From the attached diagram, <ABC = 3x+4
<ABC = 3(15)+4
<ABC = 45+4
<ABC = 49°