Question

seja z = a+bi. se z-17z=-3+4i quanto vale a.b?

Answer 1

$z = a+bi\\\\ z-17z^- = -3+4i\\\\ z^- = a-bi\\\\ (a+bi)-17(a-bi) = -3+4i\\\\\ (a+bi)-17a+17bi = -3+4i\\\\ -16a+18bi=-3+4i\\\\\ -16a = -3\\\\ \boxed{a=\frac{3}{16}}\\\\\ 18b = 4\\\\ \boxed{b=\frac{4}{18}}$

$a.b = \frac{3}{16}.\frac{4}{18} = \frac{12}{288} = \frac{1}{24}\\\\ \boxed{a.b = \frac{1}{24}}$