-3m(m + 8)

Expanding the expression gives:

-3m² - 24m

4d(2d + 9)

Expanding the expression gives:

8d² + 36d

To simplify the expression -3m(m + 8), we will apply the distributive property and combine like terms.

Step 1: Distribute -3m to both terms inside the parentheses:
-3m * m = -3m^2
-3m * 8 = -24m

Step 2: Combine the two terms obtained from the distribution:
-3m^2 - 24m

So, the simplified expression for -3m(m + 8) is -3m^2 - 24m.