The given expression is
-0.3(8b – 2c) +7c - 0.9(9c – 2b)
We would apply the distributive property as shown below
a(b + c) = a * b + a * c
The term outside the bracket is used to multiply the terms inside the bracket. Thus, we have
- 0.3 * 8b + - 0.3 * - 2c + 7c - 0.9 * 9c + - 0.9 * - 2b
= - 2.4b + 0.6c + 7c - 8.1c + 1.8b
The next step is to collect like terms. Thus, we have
- 2.4b + 1.8b + 0.6c + 7c - 8.1c
= - 0.6b - 0.5c
The simplified expression is
- 0.6b - 0.5c