Question 200491
Both of these equations are lines. They can be put into the form Ax + By + C = 0. That format is the "standard form" for a line.
Lines can also be described  in point/slope and point/intercept forms. 
All three forms are just different ways to write the same things (they can be transformed into each other).

To plot a line, all you need it the coordinate of two points on that line. Then draw the line through those two points and you are done. You can also make a table and then calculate a bunch of individual points. Again, this is just another way to represent the same line. 

So, for this problem, let's find two points, and then draw the line

An easy way to find points is to ask "If I set x=0, what does that make y?". Then ask "If I set y=0, what does that make x?". The answers to those two questions will allows you to know two points. Then all you do is plot those two and then draw the line through them.

Let's do the first problem. Then you cna do the second one on your own.
{{{ 12x + 4y = 20  }}}
"If I set x=0, what does that make y?"
{{{12 * 0 +4y = 20}}}
{{{4y = 20}}}
{{{y = 5}}}
So one point is (0,5)

Now do the second point.
 "If I set y=0, what does that make x?"
{{{ 12x + 4y = 20  }}}
{{{12x + 4*0 = 20}}}
{{{12x = 20}}}
{{{x = 5/3}}}
The next point is (5/3 , 0)

Now plot those two points and draw the line.
Your line looks like this --> http://www95.wolframalpha.com/input/?i=12x+%2B+4y+%3D+20+

Hope that helps