Divide, the first operation is the parentheses and then division
You apply the rule to put the exponent in front, and lower it by one. But since this is a nested expression, you apply it twice:
4*(5x^3-4)^3 * 3*5x^2 =
60x^2 (5x^3-4)^3
For a number to be divisible by 14 it needs to be both divisible by 7 and 2 which are factors of 14. Every time you have a number (x) to check if it is divisible by some larger number you find the factor of that larger number and check is the x divisible by both.
Answer: it cannot be divisible by 14.