Question

The line passing through (4, a) and (8, 1) has gradient 0.75.
Work out the value of a.

Answer 1

a = - 2

Explanation:

calculate the slope of the 2 given points and equate to 0.75

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

with (x₁, y₁ ) = (4, a ) and (x₂, y₂ ) = (8, 1 )

m =
`(1-a)/(8-4)` =
`(1-a)/(4)`

then equating

`(1-a)/(4)` = 0.75 ( multiply both sides by 4 to clear the fraction )

1 - a = 3 ( subtract 1 from both sides )

- a = 2 ( multiply both sides by - 1 )

a = - 2