1.12 Complex numbers: Cartesian form Quiz

1. Find $(3+4i)(1-2i)$.

• A. $-5-2i$
• B. $3-8i$
• C. $11+2i$
• D. $11-2i$

2. Find the modulus of $5-12i$.

• A. $7$
• B. $169$
• C. $13$
• D. $\sqrt{119}$

3. Find the conjugate of $-3+2i$.

• A. $3-2i$
• B. $-3-2i$
• C. $3+2i$
• D. $-2+3i$

4. Solve $x^{2}+4=0$.

• A. $\pm2i$
• B. $\pm4i$
• C. $\pm2$
• D. No solutions at all

5. Solve $x^{2}+2x+5=0$.

• A. $1\pm2i$
• B. $-1\pm4i$
• C. $-1\pm2i$
• D. $-2\pm4i$