I am trying to figure out the below problem

Question

First write the following equation in function notation, and then find f(-2) for the function: 5x – 2y = 8

Answer 1

So, we have the general (or standard) form of linear equation

        5x – 2y = 8

Let's convert it into slope–intercept form, or, simply, solve for "y"

   5x  –  2y  =  8  
-  5x              - 5x 
 
      - 2y   =    - 5x   +    8
 ÷ (- 2)      ÷ (- 2)    ÷ (- 2)
                5 
      y  =  —— x  –  4 
                2

Now, let's use the function notation
                  5 
    ƒ(x) = ——  x  –  4 
                 2 

                5
 ƒ(- 2) = —— • (- 2)  –  4
                2
 ƒ(- 2) = - 9