Question

4. Find s if the line through the points (7,3)
and (s, -7) has a slope of -5.

Answer 1

s = 9

Explanation:

calculate the slope m through the 2 points using the slope formula and equate to - 5

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

with (x₁, y₁ ) = (7, 3 ) and (x₂, y₂ ) = (s, - 7 )

m =
`(-7-3)/(s-7)` =
`(-10)/(s-7)`

equate m to slope of - 5

`(-10)/(s-7)` = - 5 ← multiply both sides by s - 7

- 10 = - 5(s - 7) ← divide both sides by - 5

2 = s - 7 ( add 7 to both sides )

9 = s