Complex Numbers and Quadratic Equations

The roots of a quadratic equation with real coefficients and negative discriminant are:

1. Always positive
2. Always negative
3. Complex conjugates
4. Equal real roots

The argument of a complex number represents:

1. Its magnitude only
2. Its direction angle from positive real axis
3. Its conjugate
4. Its real part

The solution of x² + 4x + 5 = 0 is:

1. -2 ± i
2. 2 ± i
3. -4 ± i
4. 4 ± i

If z = a + ib, then the real part of z is:

1. a
2. b
3. ib
4. a + b

The complex number 0 + 5i is represented as:

1. 5
2. 5i
3. -5i
4. 0

The quadratic equation x² - 5x + 6 = 0 has roots:

1. 2 and 3
2. -2 and -3
3. 1 and 6
4. 5 and 6

The product of a complex number and its conjugate is always:

1. Imaginary
2. Negative
3. A real number
4. Zero

If the discriminant of a quadratic equation is negative, then the roots are:

1. Real and equal
2. Real and distinct
3. Non-real complex numbers
4. Zero

The discriminant of the quadratic equation ax² + bx + c = 0 is:

1. a² + b² - c²
2. b² - 4ac
3. b² + 4ac
4. 4ac - b²

The roots of the quadratic equation x² + 1 = 0 are:

1. 1 and -1
2. i and -i
3. 0 and 1
4. 2 and -2

The value of (2 + 3i) + (4 - 5i) is:

1. 6 - 2i
2. 2 + 8i
3. 6 + 8i
4. -2 - 2i

The conjugate of the complex number 5 + 7i is:

1. 5 - 7i
2. -5 + 7i
3. -5 - 7i
4. 7 + 5i

If z = 3 + 4i, then the modulus of z is:

1. 5
2. 7
3. 12
4. 25

Which of the following is a purely imaginary number?

1. 3 + 2i
2. 5
3. 4i
4. 2 - i

The value of i² is:

1. 1
2. -1
3. i
4. -i