Question
\( f(x)=7 x^{2}+7 x-2, g(x)=6 x-7 \) find \( (f+g)(-6) \) Your Answer:
Ask by Garrett Murphy. in the United States
Mar 10,2025
Upstudy AI Solution
Tutor-Verified Answer
Answer
\( (f+g)(-6) = 165 \)
Solution
1. Write down the definitions of \( f(x) \) and \( g(x) \):
- \( f(x) = 7x^2 + 7x - 2 \)
- \( g(x) = 6x - 7 \)
2. Find the sum \( (f+g)(x) \) by adding \( f(x) \) and \( g(x) \) together:
\[
(f+g)(x) = f(x) + g(x) = (7x^2 + 7x - 2) + (6x - 7)
\]
3. Combine like terms:
- The \( x^2 \) term: \( 7x^2 \)
- The \( x \) terms: \( 7x + 6x = 13x \)
- The constant terms: \( -2 - 7 = -9 \)
\[
(f+g)(x) = 7x^2 + 13x - 9
\]
4. Substitute \( x = -6 \) into \( (f+g)(x) \):
\[
(f+g)(-6) = 7(-6)^2 + 13(-6) - 9
\]
5. Evaluate step by step:
- Calculate \((-6)^2\):
\[
(-6)^2 = 36
\]
- Multiply by 7:
\[
7 \times 36 = 252
\]
- Multiply 13 by \(-6\):
\[
13 \times (-6) = -78
\]
- Now sum the results:
\[
(f+g)(-6) = 252 - 78 - 9
\]
6. Final computation:
\[
252 - 78 = 174
\]
\[
174 - 9 = 165
\]
Therefore, the final answer is:
\[
\boxed{165}
\]
Answered by UpStudy AI and reviewed by a Professional Tutor
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Mind Expander
To find \((f+g)(-6)\), we first need to compute \(f(-6)\) and \(g(-6)\) and then sum the results. First, let's calculate \(f(-6)\): \[ f(-6) = 7(-6)^2 + 7(-6) - 2 \] \[ = 7(36) - 42 - 2 \] \[ = 252 - 42 - 2 \] \[ = 210 - 2 \] \[ = 208 \] Now, let's calculate \(g(-6)\): \[ g(-6) = 6(-6) - 7 \] \[ = -36 - 7 \] \[ = -43 \] Now, we can find \((f+g)(-6)\): \[ (f+g)(-6) = f(-6) + g(-6) \] \[ = 208 - 43 \] \[ = 165 \] Thus, \((f+g)(-6) = 165\).