Question

Rationalize the denominator of ..........

Answer 1

\[\frac{ 4 }{ 2+7i }*\frac{ 2-7i }{ 2-7i }\]
\[\frac{ 8-28i }{ ? }\]
can you try to do the denominator

Answer 2

what did you get?... :D

Answer 3

the numerator is = 4(2-7i) = 8-28i yes or no?
next the denominator is = (2+7i)(2-7i)= ______________?

Answer 4

if we have (a+b)(a-b)=a^2-b^2 also
if we have (a+bi)(a-bi)=[a^2-(bi]^2 did you get this one ? yes or no?... :D

Answer 5

@ evergirl what did you get?