Question

1. find the sum. $(9r^2 + 4r - 7) + (3r^2 - 3r)$

Explanation:

Step1: Remove parentheses

To add the two polynomials, we first remove the parentheses. Since there is no negative sign in front of the second parentheses, we can just write the terms as they are: \(9r^{2}+4r - 7+3r^{2}-3r\)

Step2: Combine like terms

• For the \(r^{2}\) terms: \(9r^{2}+3r^{2}=(9 + 3)r^{2}=12r^{2}\)
• For the \(r\) terms: \(4r-3r=(4 - 3)r=r\)
• The constant term remains \(-7\)

Step3: Write the result

Combine all the combined like - terms: \(12r^{2}+r - 7\)

Answer:

\(12r^{2}+r - 7\)