The inclination of y-axis is:

1. 0°

2. 45°

3. 90°

4. 180°

The slope of a line whose inclination is 30°, is:

1. $\dfrac{1}{2}$

2. $\sqrt{3}$

3. 1

4. $\dfrac{1}{\sqrt{3}}$

The slope of a vertical line is:

1. 0

2. 1

3. 90

4. not defined

The slope of a line passing through two given points A(x₁, y₁) and B(x₂, y₂) is given by:

1. $m = \dfrac{x$2 - x1}{y2 - y1}

2. $m = \dfrac{y$2 \times y1}{x2 \times x1}

3. $m = \dfrac{x$2 \times x1}{y2 \times y1}

4. $m = \dfrac{y$2 - y1}{x2 - x1}