Equations of a Line

Question

find the equation of the line containing the given pair of points, (-5,-8) (-1,-9) the equation of a line in slope intercept form is y=

Answer 1

Say the points :

Slope intercept form

Line equation

Substitute the values and

.

So,the slope intercept form is .

Answer 2

Slope-intercept form line equation is y = mx + b, where m is slope and b is y-intercept.

Let the points are (x₁, y₁) = (- 5, - 8) and (x₂, y₂) = (- 1, - 9).

Slope (m) = [(y₂ - y₁)/(x₂ -x₁)]

m = (- 9 - (- 8))/(- 1 - (- 5))

m  = (- 9 + 8)/(- 1 + 5)

⇒ m = - 1/4.

Now, the line equation is y = (- 1/4)x + b.

Find the y - intercept by substituting any point in the line equation say (x, y) = (- 5, - 8).

- 8 = (- 1/4)(- 5) + b

b = - 8 - (5/4)

b = (- 32 - 5)/4

⇒ b = - 37/4.

The line equation in slope - intercept - form is y = (- 1/4)x - (37/4).