19. Resolva, em Re, a equaçio: \[ \left|\begin{array}{cccc}x & 0 & 1 & 2 \\ 0 & 0 & -1 & 1 \\ -3 & -1 & 2 & 0 \\ 1 & 2 & 1 & 3\end{array}\right|=-31 \]

3. \( x^{2}-25=0 \)

\( \begin{array}{lll}\text { 5. } 8 y+5<3 & \text { 6. } 3 p+2 \geq-10 & \text { 10. }-1.3 \geq 2.9-0.6 r \\ \text { 8. }-2>\frac{m}{6}-7 & \text { 9. }-1.2 b-5.3 \geq 1.9 & \text { 10. }\end{array} \)

Simpept 3.13 - Multiplying Complex Numbers Sollowing expression: \( 2 i(5+3 i) \)

What are \( a \) and \( b \) when you write \( \sqrt{-16} \) in the form \( a+b i \), where \( a \) and \( b \) are real numbers?

\begin{tabular}{l|l|}\hline 2. Explain to someone who missed class how you would write \( (3-5 i)(-2+4 i) \) in the form \( a+b i \), \\ where a and b are real numbers. \end{tabular}