Question

A line has a slope of 4 and includes the points ( – 6, – 10) and ( – 5,f). What is the value of f?

Answer 1

f = -6

Explanation:

slope can be found by taking the difference of the y-values over the difference of the x-values

the x-values are -6 and -5

the y-values are -10 and f

we can set up the following to find 'f':

(-10 - f) / -6 - (-5) = 4

-10 - f / -1 = 4 or

`(-10-f)/(-1)` =
`(4)/(1)`

the above is a proportion which can be solved by cross-multiplying:

1(-10-f) = -4

-10 - f = -4

add 10 to each side:

-f = 6

therefore,

f = -6

CHECK:

-10 - (-6) / -6 - (-5) should equal 4

`(-4)/(-1)` = 4

This checks out