Problem
Given two matrices A = [[2, 3], [4, 5]] and B = [[1, 2], [3, 4]], find the result of 2A - B.
Solution
Step 1 ：First, calculate 2A. 2A = 2 * [[2, 3], [4, 5]] = [[4, 6], [8, 10]]
Step 2 ：Next, subtract B from 2A. 2A - B = [[4, 6], [8, 10]] - [[1, 2], [3, 4]] = [[3, 4], [5, 6]]
