Atruck has a maximum weight capacity of 20 tons of eight crates of 6 gallon water bottles winning an average of .8 ton per crate and six crates of 1 gallon water bottles each crate wearing an average of 1.2 tons are already loaded into the truck how many additional creative 6 gallon water bottles in the loaded into the truck without exceeding its way capacity

If the equation contains any fractions use the least common denominator to clear the fractions.  We will do this by multiplying both sides of the equation by the LCD.  

Also, if there are variables in the denominators of the fractions identify values of the variable which will give division by zero as we will need to avoid these values in our solution.

Simplify both sides of the equation.  This means clearing out any parenthesis, and combining like terms.

Use the first two facts above to get all terms with the variable in them on one side of the equations (combining into a single term of course) and all constants on the other side.

If the coefficient of the variable is not a one use the third or fourth fact above (this will depend on just what the number is) to make the coefficient a one.  

Note that we usually just divide both sides of the equation by the coefficient if it is an integer or multiply both sides of the equation by the reciprocal of the coefficient if it is a fraction.