(3r²+7r+1)+(4r² - 8r-2)
A) 7r^2 + 15r - 1
B) 7r^2 - r - 1
C) 7r^2 - 15r - 3
D) r^2 - r - 1
The expression simplifies to 7r² - r - 1. Therefore, the answer is B) 7r² - r - 1.
To add the two expressions (3r²+7r+1) and (4r² - 8r-2), we need to combine like terms.
First, let's combine the like terms with the same degree of r²:
(3r² + 4r²) = 7r²
Next, let's combine the like terms with the same degree of r:
(7r - 8r) = -r
Finally, let's combine the constant terms:
(1 - 2) = -1
Putting all these terms together, we have:
7r² - r - 1
Therefore, the correct answer is B) 7r² - r - 1.