Answer:

1. (-2xy³) • (-5x⁶y³) = 10x^(1+6)y^(3+3) = 10x⁷y⁶

2. (p²r⁴t⁵) • (-2p²t²) = -2p^(2+2)t^(5+2) = -2p⁴t⁷

3. (2ac⁵) • (4b²c²) • (6a⁸b) = 48a^(1+8)b^(1+2)c^(5+2) = 48a⁹b³c⁷

4. (10d⁶ • 3ed⁴) ÷ (5ed¹⁰) = (10d⁶ • 3ed⁴) / (5ed¹⁰) = (30d^(6+1)e^(1+4)) / (5e^(1+10)) = 6d⁷e⁵

5. (-16a³bc² ÷ 4a²c²) • 5abc = (-16/4)(a^(3-2))b^(1+1)c^(2-2) • 5abc = -4ab⁴c⁰ • 5abc = -20a^(1+1)b^(4+1)c^(0+1) = -20a²b⁵c