Perhaps you have p = [2, -1; 3, 4] where commas separate columns and semicolons separate rows. Then
3p + 2q
= 3[2, -1; 3, 4] + 2[5, 4; -2, 6]
= [6, -3; 9, 12] + [10, 8; -4, 12] (the multiplier is applied to every term)
= [16, 5; 5, 24] (corresponding terms are added)
In your format as we understand it, this would be
(16/5 5/24)
3p + 2q
= 3[2, -1; 3, 4] + 2[5, 4; -2, 6]
= [6, -3; 9, 12] + [10, 8; -4, 12] (the multiplier is applied to every term)
= [16, 5; 5, 24] (corresponding terms are added)
In your format as we understand it, this would be
(16/5 5/24)