Question

Find the value of y so that the points (-5,10) and (3,y) lie on a line with slope -3/8.

Answer 1

y = 7

Explanation:

calculate the slope m using the gradient formula

m = ( y₂ - y₁ ) / ( x₂ - x₁ )

with (x₁, y₁ ) = (- 5, 10) and (x₂, y₂ ) = (3, y)

m =
`(y-10)/(3+5)` =
`(y-10)/(8)`

For this to equal -
`(3)/(8)`

since the denominators are equal, equate the numerators

y - 10 = - 3 ( add 10 to both sides )

y = 7