Quadratic Equations with Complex Roots

9000035608

Level: 
C
The equation \[ x^{2} - 2\mathrm{i}x + q = 0 \] with a parameter \(q\in \mathbb{C}\) has a solution \(x_{1} = 1 + 2\mathrm{i}\). Find the second solution \(x_{2}\) and the parameter \(q\).
\(x_{2} = -1,\ q = -1 - 2\mathrm{i}\)
\(x_{2} = -1 - 4\mathrm{i},\ q = 9 - 6\mathrm{i}\)
\(x_{2} = 1 - 4\mathrm{i},\ q = 7 - 4\mathrm{i}\)
\(x_{2} = 1,\ q = -1 - 2\mathrm{i}\)
\(x_{2} = -1,\ q = 1 + 2\mathrm{i}\)

9000035602

Level: 
C
Find the values of the parameter \(m\in \mathbb{C}\) which guarantee that the following quadratic equation has a double solution. \[ mx^{2} - 2x - 1 + \mathrm{i} = 0 \]
\(m = -\frac{1} {2} -\frac{1} {2}\mathrm{i}\)
\(m = -1\)
\(m = -1 + \mathrm{i}\)
\(m = -\frac{1} {2} + \frac{1} {2}\mathrm{i}\)

9000022803

Level: 
B
Establish the values of the parameter \(t\) which ensure that the equation \[ x^{2} + tx + t + 8 = 0 \] with an unknown \(x\) has complex solutions with a nonzero imaginary part.
\(\left (-4;8\right )\)
\(\left [ -4;8\right ] \)
\(\left (-\infty ;-4\right )\cup \left (8;\infty \right )\)
\(\left (-\infty ;-4\right ] \cup \left [ 8;\infty \right )\)

9000019808

Level: 
B
Assuming \(x\in \mathbb{C}\), find the solution set of the following equation. \[ x\left (x + 1\right )\left (x^{2} + 1\right ) = 0 \]
\(\left \{-1;0;-\mathrm{i};\mathrm{i}\right \}\)
\(\left \{-1;0;1;-\mathrm{i};\mathrm{i}\right \}\)
\(\left \{-1;1;-\mathrm{i};\mathrm{i}\right \}\)
\(\left \{-1;0;-\mathrm{i}\right \}\)