Are the functions given below power functions?

? Power function Not a power function  1. $y = 2 / (x^3)$

? Power function Not a power function  2. $y = x^3 / 2$

? Power function Not a power function  3. $y = 12 \cdot 14^x$

? Power function Not a power function  4. $y = 3x^3 + 2x^2$

? Power function Not a power function  5. $y = \sqrt{4x^4}$

? Power function Not a power function  6. $y = 14x^{12}$