Answer:
[tex]\left[\begin{array}{ccc}9\\10\\\end{array}\right][/tex]
Step-by-step explanation:
Evaluate 3a by multiplying each element by 3
3a = 3 [tex]\left[\begin{array}{ccc}2\\4\\\end{array}\right][/tex] = [tex]\left[\begin{array}{ccc}3(2)\\3(4)\\\end{array}\right][/tex] = [tex]\left[\begin{array}{ccc}6\\12&\\\end{array}\right][/tex], then
3a + b
= [tex]\left[\begin{array}{ccc}6\\12\\\end{array}\right][/tex] + [tex]\left[\begin{array}{ccc}3\\-2\\\end{array}\right][/tex] ← sum corresponding elements
= [tex]\left[\begin{array}{ccc}6+3\\12-2\\\end{array}\right][/tex]
= [tex]\left[\begin{array}{ccc}9\\10\\\end{array}\right][/tex]
