Question

efetue : (6+i).(6-1)

Answer 1

$(6+i)\cdot(6-1)=(6+i)\cdot5\\(6+i)\cdot(6-1)=5\cdot(6+i)\\(6+i)\cdot(6-1)=5\cdot6+5\cdot i\\\\\boxed{\boxed{(6+i)\cdot(6-1)=30+5i}}$

Answer 2

$(6 + i)(6 - 1) \\ \\ 36 - 6 + 6i - i \\ \\=> 30 +5i$