Terms can be added or subtracted to form an expression.

Consider the expression  . We want to combine the two terms and write the expression in the form  , where   and   are constants, and  .

What is a special kind of expression where each term is a constant, variable or a product of constants and variables.

When adding or subtracting fractions, add or subtract the

From the nth term equation given which consists of lower terms in the sequence the explicit formula is obtained. The lower terms are substituted in much lower terms and finally all terms on right are expressed in terms of n. This technique for solving using is called

Simplify the expression. Write your answer in standard form.