 NY Regents Exam   Teasers   IQ Tests   Chemistry   Biology   GK   C++   Recipes   Search <  a href="/cgi/members/home.cgi" class="toplink">Members   Sign off Print Preview

# Algebra Homework Help : Substitution in Algebraic Expressions

 Preparation Just what you need to know !

## How to Simplify Algebraic Expressions by Substitution ?

Simplification and evaluation of an algebraic expression is possible by substituting the various letter variables with given expressions and specific values. It is important to write each substitution in parentheses, and then simplify the expression carrying out the operations in the correct order (Parentheses, Exponents, Multiplication, Division, Addition and Subtraction).

Example :
Given b = -3, c = a3 and d = a + 2, simplify c(a - 3b) + 7a3b + a3d
Now, c(a - 3b) + 7a3b + a3d
= (a3) (a - 3(-3)) + 7a3(-3) + a3(a + 2)
[on substituting b everywhere by (-3), c by (a3), and d by (a + 2)]
= a4 + 9a3 - 21a3 + a4 + 2a3
= 2a4 - 10a3
The simplified result may also be written as 2a3(a - 5).

29 more pages in Algebra