Question

Find the equation (in slope-intercept form) of the line passing through the points with the given coordinates.

(1, -1), (2, -3)

Answer 1

is parallel to the -axis. If the coordinates of the points and are (, 2) and (8, 6), respectively, find the value of .

Answer 2

y = -2x + 1

Explanation:

The slope-intercept form of an equation of a line:

`y=mx+b`

m - slope

b - y-intercept

The formula of a slope:

`m=(y_2-y_1)/(x_2-x_1)`

We have two points (1, -1) and (2, -3).

Substitute:

`m=(-3-(-1))/(2-1)=(-2)/(1)=-2`

Put it and the coordinates of the point (1, -1) to the equation of a line:

`-1=-2(1)+b`

`-1=-2+b` add 2 to both sides

`1=b\to b=1`

Finally:

`y=-2x+1`