Plsss help asappp :,)

2. x² + 8y²

3. -6 - 2y³ + 10y²

4. 3a² - 2a

Step-by-step explanation:

2. Two minuses make a plus.

(10x² + 4y²) - (9x² - 4y²) = 10x² + 4y² - 9x² + 4y²

Evaluate like terms.

10x² + 4y² - 9x² + 4y² = x² + 8y²

3. When multiplying terms in a bracket, you must multiply the term outside the bracket to all the terms in the bracket.

-2y²(3y² + y - 5) = (-2y² × 3y²) + (-2y² × y) + (-2y² × -5)

                          = (-6) + (-2y³) + (10y²)

                          = -6 - 2y³ + 10y²

4. When dividing terms in a bracket, you must divide all the terms in the bracket to the term outside the bracket.

(12 - 8a³) ÷ 4a² = (12 ÷ 4a²) + (- 8a³ ÷ 4a²)

                            = (3a²) + (-2a)

                            = 3a² - 2a

3

step-by-step explanation:

r and t.

both are 64 degrees.