There are three basic equations to keep in mind.  The first one is the linear equation.
    A linear equation is simply an equation in which one piece of information is missing.
    The missing piece of information is called the variable.

Ex: 9x=18. . . The "x" is the variable of this linear equation.
    With 9x=18, we are trying to find the variable, so. . .

1. 4x=12              x = 3      4    4 2. 36x = 4            x = 1/9        36    36  3. 3x+ 8 = 20         3x = 20-8         3x = 12          3x = 12        x = 4          3      3  4. 5x - 9 = 16          5x = 16 + 9          5x = 25          5x = 25       x = 5           5      5

Okay, that's enough of linear equations.  I hope you understand them.  Next are literal equations.  A literal equation is one that has no numerical representation.  Here's a nice little step-by-step chart to help you along your way.
 

Problem: d= rt	Here, you are trying to isolate   "t"
d = rt    r     r	Right here, we need to get rid of the "r" so the "t" can be alone
d = t     r	Now, the "t" is alone.  Probelm solved!

    Just in case that was over your head, which I couldn't blame you for, I'm going to give you a list of examples!

What To Isolate	Problems	Solutions
r	m-r = ab	r = -ab - m
e	e(f)=l	e = l        f
b	g=cb	g = b c
c	g=cb	g  = c b
a	a+b+f= gh	a = gh- b - f

    Now that everyone understands literal equations, we're going to move on to our final topic, and the longest. . . . the 3 equations of a line!

The first one is called SLOPE INTERCEPT!!!!  This is the one that you'll be seeing for a LONG time!  It goes a little something like this. . . . .y = mx + b!  I find it important to tell you what each variable means, otherwise this won't help you very much.
 

The Variable	What It Means
y	It is the coordinate on the Y axis.
m	It is the slope intercept, also called the X-intercept.
x	It is the coordinate on the X-axis.
b	It is the Y-intercept.

Here are some examples of how you can use this to your advantage:
1) Q: If you have two coordinates (3, 5), what is the slope intercept equation?
   A: y = mx + b
       y = (3)x + 5
 

2) Q: The coordinates are (4, 8). Solve.
   A:  y = mx + b
         y = 4x + 8

That was the easy one.  Moving on. . . .

    The next equation is called STANDARD FORM.  Personally, I think that this is the hardest,    but maybe you'll get it.

    The standard form equation is. . . ax + by = c.
Once again, I shall give you a chart to explain the variables.
 

The Variables	What It Means
a	It is a coordinate on the X-axis
x	It is the X or Slope- Intercept
b	It is a coordinate on the Y-axis
y	It is the Y-intercept
c	It is the slope of the line.

    Let's try some examples!

1) Q: If the slope of the line is 4, and two coordinates are (3, 5), what is the equation solution for standard form?
   A: ax + by = c
        3x + 5y = 4

2) Q:  The Y-intercept is 8, and the slope-intercept is 3.  Solve.
   A:   ax + by = c
          a3 + b8 = c

There, maybe that wasn't so hard after all!  Who0-hoo!

    All right, everybody, last little equation, and then you will all be math geniuses!   We are going to conquer the point-slope equation, and, as expected, here is a table to help you out!

The point-slope equation is Y1- Y = M(X1-X)
 

Problem: The coordinates are (3, 5) and the slope is 4.  Solve	5-Y = 4(3-X)
You're not done yet.	5-Y = 12 - 4X

You're finished!  Here are some links to help you out if you're still a bit confused!