Answer:
x=10.5
Step-by-step explanation:
5(x+3)=(6)(12)-[.5(6)(12-x)]
5x+15=72-36+3x
reduce
2x=21
check
5(10.5+3)=(6)(12)-[.5(6)(12-10.5)]
52.5+3=72-4.5
67.5=67.5