Question

1. $(4r^{3}+r^{4}-2r)+(8r^{4}+3r^{3}+8r)$

Explanation:

Step1: Remove parentheses

Since there is a plus sign before the parentheses, the terms inside remain unchanged. So we have $4r^{3}+r^{4}-2r + 8r^{4}+3r^{3}+8r$.

Step2: Combine like - terms

Combine the $r^{4}$ terms: $r^{4}+8r^{4}=9r^{4}$. Combine the $r^{3}$ terms: $4r^{3}+3r^{3}=7r^{3}$. Combine the $r$ terms: $- 2r+8r = 6r$.

Answer:

$9r^{4}+7r^{3}+6r$