Let's simplify the expression step by step:

12(x^3 - 2) - 7x(x^2 - 1) = 5x^3 + 2x + 6

Expanding the terms inside the parentheses:

12x^3 - 24 - 7x^3 + 7x = 5x^3 + 2x + 6

Combining like terms:

5x^3 - 24 + 7x = 5x^3 + 2x + 6

Rearranging the terms:

5x^3 - 5x^3 + 7x - 2x = 6 + 24

Simplifying the equation:

5x = 30

Dividing both sides by 5:

x = 6

Therefore, the solution to the equation is x = 6.