1)- 7a² + 2вc - 8c² + 4c² + 2a² - 9 = 2) 2a³ + a² - 17 - 3²+ a⁴+ a² - 20 = 3) 2aв² + 3a²в - 7aв² + 4aв =

Let's simplify each expression step by step.

1. Simplifying \( -7a^2 + 2bc - 8c^2 + 4c^2 + 2a^2 - 9 \):

Combine like terms:

• \( -7a^2 + 2a^2 = -5a^2 \)
• \( -8c^2 + 4c^2 = -4c^2 \)

So the expression becomes:

\[ -5a^2 + 2bc - 4c^2 - 9 \]

2. Simplifying \( 2a^3 + a^2 - 17 - 3^2 + a^4 + a^2 - 20 \):

First, compute \( 3^2 = 9 \).

Then, combine like terms:

• \( a^4 + 2a^2 + 2a^3 - 17 - 9 - 20 = a^4 + 2a^3 + 2a^2 - 46 \)

So the expression becomes:

\[ a^4 + 2a^3 + 2a^2 - 46 \]

3. Simplifying \( 2ab^2 + 3a^2b - 7ab^2 + 4ab \):

Combine like terms:

• \( 2ab^2 - 7ab^2 = -5ab^2 \)

So the expression becomes:

\[ -5ab^2 + 3a^2b + 4ab \]

This can be combined as:

\[ 3a^2b - 5ab^2 + 4ab \]

Thus, the simplified expressions for each problem are:

1. \( -5a^2 + 2bc - 4c^2 - 9 \)
2. \( a^4 + 2a^3 + 2a^2 - 46 \)
3. \( 3a^2b - 5ab^2 + 4ab \)