Answer: 3a^3 + 4a^2 - a + 5
Explanation:
1. (4x^3 + 2x^2 - 4x + 3) + (7x^3 - 4x^2 + 7x + 8)
combine terms with same exponent;
(4x^3 + 7x^3) + (2x^2 - 4x^2) + (-4x + 7x) + (3 +8)
= 11x^3 + (-2x^2) + 3x + 11
= 11x^3 - 2x^2 + 3x +11.............final answer
2. 3a^3 + 8a - 6 and 4a^2 -9a +11
combine terms with same exponent;
3a^3 + 4a^2 + (8a - 9a) + (-6 + 11)
= 3a^3 + 4a^2 + (-a) + 5
= 3a^3 + 4a^2 - a + 5...........final answer