$\left(7+9i\right)+\left(3-4i\right)$ 

 $5i\left(1-2i\right)$  

 $2i\left(3+4i\right)$  

 $\left(1+2i\right)-\left(9-4i\right)$  

 $\left(4+3i\right)\left(4-3i\right)$  

Calculate:

(4 − 7i) − (-3 + 6i)

Calculate:

(1 − 2i) + (-4 + 2i)

Calculate (multiply):

(1 − 2i)(6 + 5i)

Multiply:

(2-5i)(2+5i)