Skip to content / Đến nội dung
ThichHocToan.com

1991 AMC 12 Question 18

AMC12 · 1991 AMC 12

Question 18

If $S$ is the set of points $z$ in the complex plane such that $(3+4i)z$ is a real number, then $S$ is a
  1. right triangle
  2. circle
  3. hyperbola
  4. line
  5. parabola