Post a New Question | Current Questions | Live Experts | Download
Homework Help: Math: Algebra: Substitution
Provided by FreeMathHelp.com
 Substitution is
the process of replacing a variable in an expression with its
actual value. If you are given an equation like 4z + 6 = x + z,
told that z = 2, and asked to solve for x, what do you do? The
first step is to substitute 2 for every 'z' in the problem.
This
leaves us a more manageable equation, 4 * 2 + 6 = x + 2 (remember
that * means multiply). After simplifying things a little we get
14 = x + 2. Subtract 2 from each side and you'll discover that
x = 12.
Substitution
can also involve more complicated problems, like 5x^2 + 2y -6
= y, where y = -1 and x = 4. Just substitute in the same way,
placing the value of each variable in place of the letter and
simplifying.
There
is another form of substitution. This is where we insert a variable
to stand for a particular expression. In some cases you will be
dealing with incredibly complex problems, and it may be easier
to substitute a variable, like y for part of the problem. Then,
when you have solved the value of y, you can plug back in the
original expression.
Copyright © 2002 Ted Wilcox
This lesson was reproduced on Jiskha Homework Help with permission from the author.
Homework Help: Math: Algebra
For Further Reading
|
