Question

The points (–7, 7) and (6, –6) fall on a particular line. What is its equation in slope-intercept form?

Answer 1

y=-x

Explanation:

Slope =1

Substitute m= -1 into the equation:

y= -1x +c

y= -x +c

To find the value of c, substitute a pair of coordinates.

When x= -7, y= 7,

7= -(-7) +c

7= 7 +c

c= 7 -7

c= 0

Thus, the equation of the line is y= -x.

Answer 2

y= -x

Explanation:

Slope-intercept form

y= mx +c, where m is the slope and c is the y-intercept

`\boxed{slope = (y1 - y2)/(x1 - x2) }`

Slope

`= (7 - ( - 6))/( - 7 - 6)`

`= (7 + 6)/( - 13)`

`= (13)/( - 13)`

`= - 1`

Substitute m= -1 into the equation:

y= -1x +c

y= -x +c

To find the value of c, substitute a pair of coordinates.

When x= -7, y= 7,

7= -(-7) +c

7= 7 +c

c= 7 -7

c= 0

Thus, the equation of the line is y= -x.