Answer:
x = 23; not extraneous
Explanation:
A solution is extraneous if it does not satisfy the original equation. Extraneous solutions can sometimes be introduced in the process of solving radical and rational function equations.
Solution
Squaring both sides of the given equation, we get ...
√(3x +12) = 9
3x +12 = 81 . . . . . . square both sides
x +4 = 27 . . . . . . . divide by 3
x = 23 . . . . . . . . . . subtract 4
Check
There is only one solution, and it satisfies the equation:
√(3×23 +12) = √81 = 9
The solution x = 23 is not extraneous.