Consider the complex numbers $3+4i$ and $2+5i$.

1. Suppose you want to add them. For this, just add them as you would add real numbers:

   The result should be $5+9i$.

2. Suppose you want to multiply them. Put each number in brackets and multiply each bracket:

   

   The result should be $-14+23i$.

3. Suppose you want to divide them. Display a fraction by pressing and select . Put the numbers in each part of the fraction:

   

   The result should be approximately $0.897-0.241i$ or $\frac{26}{29}-\frac{7}{29}i$.

   If you want to switch from fraction to decimal writing, press and select Number > Convert to Decimal.

Suppose you have to solve the equation $x^2+x+1=0$

1. Ensure the right-hand side is $0$.
2. Press , select Algebra > Complex > Solve, and the command csolve() will appear.
3. Enter the equation and the variable of interest after a comma inside the brackets.
4. Press . The solutions are displayed :

   

   The results should be $x_1=-\frac{1}{2}+\frac{\sqrt{3}}{2}i$ and $x_2=-\frac{1}{2}-\frac{\sqrt{3}}{2}i$ or in decimal form (rounded): $x_1=-0.5+0.866i$ and $x_2=-0.5-0.866i$.

   To change from fraction to decimal, press and select Number > Convert to Decimal.