Simplify (3a^2c)(-3bc^2)

$(3 a^{2} c) (- 3 b c^{2})$

Multiply $c$ by $c^{2}$ by adding the exponents.

Move $c^{2}$ .

$3 a^{2} (c^{2} c) (- 3 b)$

Multiply $c^{2}$ by $c$ .

Raise $c$ to the power of $1$ .

$3 a^{2} (c^{2} c^{1}) (- 3 b)$

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$3 a^{2} c^{2 + 1} (- 3 b)$

Add $2$ and $1$ .

$3 a^{2} c^{3} (- 3 b)$

Multiply $- 3$ by $3$ .

$- 9 a^{2} c^{3} b$