Accepted Answer
[tex](2+7i)(2-7i)=2^2-(7i)^2=4-49\vfot(-1)=4+49=53\\\\-------------------------------\\i=\sqrt{-1}\\\\i^2=-1[/tex]
Suggested Answer
[tex](2+7i)(2-7i)=4-14i+14i-49i^2\\
\\
4+49=53[/tex]
Related Question in Mathematics
[tex](2+7i)(2-7i)=2^2-(7i)^2=4-49\vfot(-1)=4+49=53\\\\-------------------------------\\i=\sqrt{-1}\\\\i^2=-1[/tex]
[tex](2+7i)(2-7i)=4-14i+14i-49i^2\\
\\
4+49=53[/tex]