Algebra Review

A few basic facts you will need to remember

 

 but     and  are undefined

 and does not factor          for example do not factor.

 

                   

 

  always has one real solution whether a is positive or negative.

                  

 

               

 

     ,  

 

Quadratic Formula:  The solution(s) to  are and

                                                                                               

 

Exponents:      for x not 0, ,      

 

            

 

      ,   

 

      ,    

 

 

 

 

 

 

Cancellation: Only cancel common factors, not summands.

    Ex.  

      x is not a factor of the numerator and cannot be cancelled.

 

   x + 2 is not a factor of the denominator and cannot be cancelled.

 

   for

 

Miscellaneous problems you will see again in similar form:

Collect terms and factor   .  Each summand contains  so we can factor it out.   This leaves =

 

Practice problem:  Solve    

 solution 

 

 

Rationalize the numerator of .  To do this multiply by 1 in the form .     .

Notice that the original expression was undefined at h=0 but the last expression is defined at h=0.

 

Solve     Put it over a common denominator. To do this multiply   by 1 in the form of .  This leaves   which is 0 at   Both are between -1 and 1 where the expressions are defined.