I believe you have to use power rules for these so for the numerator (x^5yz^4)^3 the power outside of the bracket will multiply with the powers inside the bracket in order to simplify this part so the numerator of the fraction would be x^15y^3z^12 (because 5x3=15, 1x3=3, 4x3=12)
Next simplify the fraction this is done by subtracting the powers so x^15y^3z^12/x^3yz =x^12y^2z^11 (because any singular letter term ie y can also be seen as y^1, using this 15-3=12, 3-1=2, 12-1=11) this is your final answer so a=12 b=2 and c=11