Question

How do you graph `4x+5y-20=0`?

Answer 1

You may start by recognizing that it is a linear function (between us...all the variables are on...a line...there are not `x` in powers, in roots....in a fraction or in other functions).
The graph of a linear fuction is a straight line and you need only 2 points to plot it.
You can chose 2 values of `x` and evaluate the correspondent `y`. These will be the coordinates of the two points of your line (try to choose "easy" `x`!).
Let's chose:
`x=0 -> y=20/5=4`
`x=3 -> y=(20-12)/5=8/5=1.6`

So you get: