Use the given line and the point not on the line to answer the question.

What is the point on the line perpendicular to the given line, passing through the given point, that is also on the [tex]$y$[/tex]-axis?

A. [tex]$(-3.6, 0)$[/tex]
B. [tex][tex]$(-2, 0)$[/tex][/tex]
C. [tex]$(0, -3.6)$[/tex]
D. [tex]$(0, -2)$[/tex]



Answer :

To determine the point on the line that is perpendicular to the given line and passing through a given point on the [tex]\( y \)[/tex]-axis, we should first identify the characteristics of the given line and then apply these characteristics to find the required point.

1. Identify the given line: The given line passes through the points [tex]\((-2, 0)\)[/tex] and [tex]\((0, -2)\)[/tex].

2. Calculate the slope of the given line:
- The slope formula is given by:
[tex]\[ \text{slope} = \frac{y_2 - y_1}{x_2 - x_1} \][/tex]
- Plugging in the coordinates of the given points:
[tex]\[ \text{slope} = \frac{-2 - 0}{0 - (-2)} = \frac{-2}{2} = -1 \][/tex]

3. Determine the slope of the line perpendicular to the given line:
- The slope of a line perpendicular to another line is the negative reciprocal of the original slope.
- The negative reciprocal of [tex]\(-1\)[/tex] is [tex]\(1\)[/tex].

4. Find the equation of the line perpendicular to the given line that passes through a point on the [tex]\( y \)[/tex]-axis:
- Since this perpendicular line passes through the [tex]\( y \)[/tex]-axis, its [tex]\( x \)[/tex]-coordinate is [tex]\( 0 \)[/tex], making the point [tex]\((0, y)\)[/tex].
- The general equation of a line with a slope [tex]\( m \)[/tex] passing through the point [tex]\((x_1, y_1)\)[/tex] is:
[tex]\[ y - y_1 = m(x - x_1) \][/tex]
- Substituting [tex]\( m = 1 \)[/tex] and [tex]\( (x_1, y_1) = (0, y) \)[/tex]:
[tex]\[ y - y = 1(x - 0) \implies y = x + y \][/tex]

5. Check the points provided as options to determine which point lies on both the perpendicular line and the [tex]\( y \)[/tex]-axis:
- Points given: [tex]\((-3.6, 0)\)[/tex], [tex]\((-2, 0)\)[/tex], [tex]\((0, -3.6)\)[/tex], [tex]\((0, -2)\)[/tex].

6. Identify the point on the [tex]\( y \)[/tex]-axis that also satisfies the equation of the line perpendicular to the given line:
- Clearly, among the given options, the point [tex]\((0, -2)\)[/tex] is on the [tex]\( y \)[/tex]-axis and is also where the perpendicular line intersects the [tex]\( y \)[/tex]-axis.

Therefore, the point on the line perpendicular to the given line, passing through the given point on the [tex]\( y \)[/tex]-axis, is:
[tex]\[ (0, -2) \][/tex]