Question

write an equation in slope-intercept form of the line that passes through the points (-5,-3) and (1,9)

Answer 1

y = 2x + 7

Explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

Calculate m using the slope formula

m =
`(y_(2)-y_(1) )/(x_(2)-x_(1) )`

with (x₁, y₁ ) = (- 5, - 3 ) and (x₂, y₂ ) = (1, 9 )

m =
`(9-(-3))/(1-(-5))` =
`(9+3)/(1+5)` =
`(12)/(6)` = 2 , then

y = 2x + c ← is the partial equation

To find c substitute either of the 2 points into the partial equation

Using (1, 9 ) , then

9 = 2 + c ⇒ c = 9 - 2 = 7

y = 2x + 7 ← equation of line