Question

Write the equation for each line: horizontal line through the point (2,5) ? vertical line containing (-9,- 3) ? Write the equation of the line and find the slope.

Answer 1

Explanation:

horizontal line through (2, 5).

that means it is a line of all points with the y-coordinate having the same value. due to the given point that y-coordinate is 5.

therefore, the equation is

y = 5

vertical line through (-9, -3).

that means it is a line of all points with the x-coordinate having the same value. due to the given point that x-coordinate is -9.

therefore, the equation is

x = -9

the slope of a line is the ratio

y coordinate difference / x coordinate difference

when going from one point on the line to another.

for y = 5 the y coordinate difference is always 0 no matter what x-value we use.

the slope is therefore 0/x = 0.

for x = -9 the x coordinate difference is always 0 no matter what y-value we use.

the slope is therefore y/0, and is therefore undefined.

Answer 2

y = 5

Explanation:

If it's a horizontal line the y will be a value that doesn't change. And vise versa if there is a vertical line.