Let \(a,b,c\) be real numbers such that
\(a+2b+3c=13\)
\(a^2 + 4b^2 + 9c^2 + 3a - 2b + 15c = 82\)
Find all possible values of \(a \). What are all the possible values?
The possible values of a are -1 and 2.
+143 
