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 $\left(2+3i\right)-\left(-6+8i\right)+\left(4-i\right)$(2+3i)−(−6+8i)+(4−i).

Simplify $-6\left(3-5i\right)$−6(3−5i).

Manipulate complex numbers and present them graphically

Apply the algebra of complex numbers in solving problems