gaokao 2023 Q1

gaokao · China · national-II 5 marks Complex Numbers Arithmetic Locating Points in the Complex Plane (Quadrant/Axis)

In the complex plane, the point corresponding to $(1+3i)(3-i)$ is located in
A. the first quadrant
B. the second quadrant
C. the third quadrant

A
$(1+3\mathrm{i})(3-\mathrm{i})=6+8\mathrm{i}$, so the corresponding point is in the first quadrant. Choose A.

In the complex plane, the point corresponding to $(1+3i)(3-i)$ is located in\\
A. the first quadrant\\
B. the second quadrant\\
C. the third quadrant