You have the following equation:
2x + y/3 = 4
In order to solve for y, proceed as follow:
2x + y/3 = 4 subtract by 2x both sides
y/3 = 4 - 2x multiply by 3 both sides
y = 3(4 -2x) apply distribution property
y = 3(4) + 3(-2x)
y = 12 - 6x order the expression
y = -6x + 12
Hence the solution for y is:
y = -6x + 12