If a = (3x ^ 2) x 5x 2, B = (4x ^ 2) x 5x 10 2, the size of a and B

If a = (3x ^ 2) x 5x 2, B = (4x ^ 2) x 5x 10 2, the size of a and B

A-B = 2-x ^ 2, when x ∈ (- radical 2, radical 2), a > b,
X < - radical 2 or X > radical 2, a < B