ALGEBRA SUBSTITUTION : METHOD
WITH EXAMPLES OF FINDING
THE VALUE OF AN
ALGEBRAIC EXPRESSION

Please study
Algebra Glossary before Algebra Substitution
if you have not already done so.

Value of an Algebraic Expression

The literal numbers or variables in an algebraic expression
can take any value allotted to them.

Thus, by putting allotted numerical values in place of literal values,
the value of an algebraic expression can be found.

The method of putting allotted numerical numbers
in place of literal numbers is called SUBSTITUTION.

Example 1 of Algebra Substitution :

If a = 2, b = 5, find the value of (i) 2a + b (ii) a +3b (iii) 10a - 4b

solution:

substituting a = 2 and b = 5, we get
(i) 2a + b = 2x2 + 5 = 4 + 5 = 9.
(ii) a + 3b = 2 + 3x5 = 2 + 15 = 17.
(iii) 10a - 4b = 10x2 - 4x5 = 20 - 20 = 0.

Example 2 of Algebra Substitution :

If x = 3, find the value of 3x² - 5x + 10

solution:

substituting x = 3, we get
3x² - 5x + 10 = 3x3² - 5x3 + 10 = 3x9 - 15 +10 = 27-15+10 = 22.

Example 3 of Algebra Substitution :

If x = 5, y = -3 and z = 2, find the value of x ² + y² + z² -2xy -2yz -2zx.

solution:

substituting x = 5, y = -3 and z = 2, we get
x² + y² + z² - 2xy - 2yz - 2zx
= (5)²+ (-3) ² + (2) ² - 2(5)(-3) - 2 (-3)(2) - 2(2)(5)

= 25 + 9 + 4 - (-30) - (-12) - (20) = 38 +30 +12 -20 = 60.

For studying about Brackets (or)
Grouping Symbols in Algebra
Go to

Algebra Simplify