Question

I need all these answered please-

1) 6i-i
2) (12+3i)-(2+6i)
3) 5i(1+2i)
4) 8+4i divided by 4

Answer 1

easy
pretend i is just a placeholder
but remember that i=√-1 so i²=-1
1.
6i-i=6i-1i=5i

2. (12+3i)-1(2+6i)
12+3i-2-6i
12-2+3-6i
10-3i

3.
5i(1+2i)
5i+10i²
5i+10(-1)
5i-10
-10+5i

4.
(8+4i)/4
(1/4)(8+4i)
8/2+4i/4
4+1i
4+i