To solve this equation, combine like terms first:

0.6y + 0.18y - 2.376 = 5.58
0.78y - 2.376 = 5.58

Now, add 2.376 to both sides:

0.78y - 2.376 + 2.376 = 5.58 + 2.376
0.78y = 7.956

Finally, divide by 0.78 on both sides to solve for y:

y = 7.956 / 0.78
y = 10.23

So, the solution to the equation is y = 10.23.