Question

Given the point (4,5) and the slope is 6, find y when x=24

Answer 1

Use the point-slope form
y-y1=m(x-x1)
Substitute
y-5=6(x-4)
Distribute
y-5=6x-24
Add 5 to both sides
y=6x-19
Substitute x with the given value
y=6(24)-19
Solve for y
y=125

Answer 2

Given the point (4, 5) and the slope of 6, find y when x = 24. 

Form: y = mx + b
5 = 6*4 + b
b = -19


f(x) = 6x - 19

Your Problem:
f(24) = 6*24 - 19
f(24) = 144-19 = 125

Cheers