Question

Find the slope of the line that passes through (1, 9) and (8, 1).

Answer 1

Slope = -1

Explanation:

m = second y - first y / second x - first x

second y = 1

first y = 9

second x = 9

first x = 1

1 - 9 = -8

9 - 8 = 8

-8/8 = -1

Answer 2

Find the slope of a line.

We mark the points: (x₁ = 1, y₁=9) and (x₂ = 8, y₂ = 1)

• X₁ = 1

• X₂ = 8

• Y₁ = 9

• Y₂ = 1

We have that the formula is:

`\boldsymbol{\sf{m=(Y_(2)-Y_(1) )/(X_(2)-X_(1)) }}`

Now we apply the formula and solve:

`\boldsymbol{\sf{m=(1-9)/(8-1) =(-8)/(7) }}`

`\boldsymbol{\sf{m=(-8)/(7) }}`

The slope of the line through (1, 9) and (8, 1) is -8/7.