mathematics sat question

Answer: A) [tex]a^{2}[/tex] + a
add the two equations together to get A.
the ones cancel eachother out and you cant add [tex]a^{2}[/tex] to a
Answer:
A) a^2 + a
Step-by-step explanation:
So the problem says "sum" which means you have to add the expressions
(a^2) - 1 and a+1
Work:
((a^2) - 1) + (a + 1)
We can simplify only the constants
(a^2) + a + 1 - 1
(a^2) + a
so the answer is A