1. Rationalise the denominator
(20+10i+10i-5)/2^2-i^2
2. Collect like terms
((20-5)+(10i+10i))/2^2-i^2
3. Simplify (20-5)+(10i+10i) to 15+20i
15+20i/2^2-i^2
4. Simplify 2^2 to 4
15+20i/4-i^2
5. Use square rule
15+20i/4-(-1)
6. Simplify brackets
15+20i/4+1
7. Simplify 4+1 to 4
15+20i/5
8. Factor out the common term 5
5(2+4i)/5
9. Cancel 5
3+4i
10. Your final answer
3+4i
Have a nice day ;D
