Probability of uniform distribution $P(Y > 12)$ , $Y = 3X^2$ and $X\sim U(-3, 4)$

Question

My Problem

Let X be a uniformally distributed random variable such that X ∈ U(-3, 4).
Let Y = 3X²
What is P(Y > 12)

Solution
P(Y > 12) = 0.43

My attempt of solving the problem
X ∈ U(-3, 4)
P(Y > 12) = P(3X² > 12) = P(X² > 4) = P(X > 2)
If we try to calculate P(X > 2) in wolfram alpha we get (see here)
0.28574

My Question
I am clearly not getting the correct answer.
What am I doing wrong?
I am very thankful for any help and/or guidance.

Answer 1

Remember that there are two square roots for any positive real number—one positive and one negative. $$\mathsf P(X^2>4)=\mathsf P((-2>X)\cup (X>2))$$