Answer: 2x^3y^4 sqrt 2x or C on edge
Step-by-step explanation:
The problem is 3+6x = 15 with x being the number of white numbers.
Isolate variable by subtracting 3 on both sides: 6x = 12.
Isolate variable by dividing 6 on both sides: x = 2
The number of white marbles is 2.