To solve this equation, first distribute the coefficients:

2(x) + 2(21) + 3(x) - 3(4) = 5(x) + 5(6)

Simplify:

2x + 42 + 3x - 12 = 5x + 30

Combine like terms:

5x + 30 = 5x + 30

Now, subtract 5x from both sides to get:

5x - 5x + 30 = 5x - 5x + 30

30 = 30

Since both sides of the equation are the same, this equation is an identity. This means that there are infinitely many solutions to this equation.