Evaluate $\left(3+6i\right)+\left(7+3i\right)$(3+6i)+(7+3i).

Evaluate $\left(9+2i\right)-\left(6-7i\right)$(9+2i)−(6−7i).

Evaluate $\left(6+9i\right)-\left(-3-4i\right)$(6+9i)−(−3−4i).

Evaluate $\left(-1+5i\right)-2$(−1+5i)−2.

Manipulate complex numbers and present them graphically

Apply the algebra of complex numbers in solving problems