1. $\frac { 3 + i } { 1 + i } =$ A. $1 + 2 i$ B. $1 - 2 \mathrm { i }$ C. $2 + \mathrm { i }$ 2. $A = \{ 1,2,4 \}$ $$B = \left\{ x \mid x ^ { 2 } - 4 x + m = 0 \right\}$$ If $A \cap B = \{ 1 \}$, then $B =$ A. $\{ 1 , - 3 \}$ B. $\{ 1,0 \}$ C. $\{ 1,3 \}$ D. $2 - i$ 3. In the ancient Chinese mathematical classic ``Suanfa Tongzong'', there is the following problem: ``Looking from afar at a seven-story pagoda, with lights doubling at each level, totaling 381 lights, how many lights are at the top?'' This means: a seven-story pagoda has a total of 381 lights, and the number of lights at each lower level is twice that of the level above it. The number of lights at the top of the pagoda is A. 1 B. 3 C. 5 [Figure]
1. $\frac { 3 + i } { 1 + i } =$\\
A. $1 + 2 i$\\
B. $1 - 2 \mathrm { i }$\\
C. $2 + \mathrm { i }$
2. $A = \{ 1,2,4 \}$
$$B = \left\{ x \mid x ^ { 2 } - 4 x + m = 0 \right\}$$
If $A \cap B = \{ 1 \}$, then $B =$\\
A. $\{ 1 , - 3 \}$\\
B. $\{ 1,0 \}$\\
C. $\{ 1,3 \}$\\
D. $2 - i$
3. In the ancient Chinese mathematical classic ``Suanfa Tongzong'', there is the following problem: ``Looking from afar at a seven-story pagoda, with lights doubling at each level, totaling 381 lights, how many lights are at the top?'' This means: a seven-story pagoda has a total of 381 lights, and the number of lights at each lower level is twice that of the level above it. The number of lights at the top of the pagoda is\\
A. 1\\
B. 3\\
C. 5\\
\includegraphics[max width=\textwidth, alt={}, center]{cd808fdb-5cf6-4ceb-9628-959ae73784cb-1_138_896_1485_663}\\