Expand and simplify $9i\left(x+7i\right)$9i(x+7i), leaving your answer in terms of $i$i.

Complete the factorisation by filling in the empty box.

Expand and simplify $\left(7+2i\right)\left(7-2i\right)$(7+2i)(7−2i).

Expand and simplify $\left(x+9iy\right)\left(x-9iy\right)$(x+9iy)(x−9iy).

Manipulate complex numbers and present them graphically

Apply the algebra of complex numbers in solving problems