Question

Consider the function represented by 9x+3y=12 with x as the independent variable. How can this function be written using function notation?

Answer 1

This function can be written in y=mx+b by getting the y by itself.

9x+3y=12 --- subtract 9x from both sides

3y=12-9x --- divide both sides by 3

y=4-3x --- change order to function notation

y=-3x+4

Answer 2

solve for y

9x+3y = 12

subtract 9x from each side

3y = 12 - 9x

divide by 3

y = 4-3x

f(x) = 4-3x