<PRE><B>Question 310369</B>
write in standard form,a+bi.

{{{(21-3i)/(1-3i)}}}
Multiply by the conjugate of the denominator over itself
{{{(21-3i)/(1-3i)}}} * {{{(1+3i)/(1+3i)}}}
FOIL the numerator and denominators (center terms cancel)
{{{(21+63i-3i-9i^2)/(1-9i^2)}}} = {{{(21+60i-9(-1))/(1-9(-1))}}} = {{{(21+60i+9)/(1+9)}}} = {{{(30+60i)/(10)}}}
Cancel 10 into 30 and 60 resulting in:
3 + 6i
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