Answer:
x = 1.4 (or 21/15)
Step-by-step explanation:
12x - 15 = 6 - 3x
+3x +3x
-----------------------
15x - 15 = 6
+15 +15
15x = 21
/15 /15
----------------------
x = 21/15 or
x = 1.4
4120
850