we have
[tex](4+7i)(3+4i)[/tex]
remember that
[tex]i^{2} =-1[/tex]
Applying the distributive property
[tex](4+7i)(3+4i)=4*3+4*4i+7i*3+7i*4i \\=12+16i+21i+28 i^{2}\\= 12+37i+28*(-1) \\=12-28+37i\\=-16+37i[/tex]
therefore
the answer is
[tex]-16+37i[/tex]
