Question

Describe and correct the error in writing an equation of the line shown

Answer 1

y = -
`(3)/(5)` x + 4

Explanation:

the student used the y- coordinates of the points in the wrong order.

The equation of a line in slope- intercept form is

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

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

with (x₁, y₁ ) = (0, 4) and (x₂, y₂ ) = (5, 1) ← 2 points on the line

m =
`(1-4)/(5-0)` =
`(-3)/(5)` = -
`(3)/(5)`

the line crosses the y- axis at (0, 4 ) ⇒ c = 4

y = -
`(3)/(5)` x + 4 ← equation of line