Cho z = 1 + 2i; w = 8 - 6i. Tính omega z/w. A. 1/25 - 1/50i; B. 2/5 - 11/5i;

Đáp án đúng là: C

$\omega =\frac{z}{w}=\frac{1+2i}{8-6i}=\frac{\left(1+2i\right)\left(8+6i\right)}{\left(8-6i\right)\left(8+6i\right)}$

$=\frac{8+16i+6i+12i^2}{8^2+6^2}=\frac{8+16i+6i-12}{8^2+6^2}$

$=\frac{-4+22i}{100}=\frac{-1}{25}+\frac{11}{50}i.$