Ответ:

1)  x^6 * x^8 = x^6+8 = x^14

2) x^8 : x^6 = x^8-6 = x^2

3) (x^6)^8 = x^6*8 = x^48

4)  (x^4)^3 * x^2  /  x^9 = x^12 *x^2 / x^9 = x^14 / x^9 = x^14 - 9 = x^5

5)  (x^4)^4 * x^2 / x^8 = x^16 * x^2 / x^8 = x^18 / x^8 = x^10