Answer:
1. x²=36
> √x²=√36
> x=±6
2. x²=81
> √x²=√81
> x=±9
3. x²-100=0
> x²=100
> √x²=√100
> x=±10
4. (x-4)²=169
> √(x-4)²=√169
> x-4=13
> x-4=13; x-4=-13
> x=13+4=17; x-4=-13+4=9
> x=17, x=9
5. x²+49=0
> x²=-49
> √x²=√-49
> x=±7i or no real solution.
