Answer:
x^15
Step-by-step explanation:
Recall these rules of exponents:
(a^m)^n = a^mn
a^m • a^n = a^(m + n)
(x^6)² • x³ = x^(2 • 6) • x³ = x^12 • x³ = x^(12 + 3) = x^15
