COLLEGE๎ALGEBRA๎
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Lesson: Algebraic Expressions
Objectives: 1. Evaluate Algebraic Expressions
An Algebraic Expression is a mathematical statement which is obtained by performing a finite
number of the following operations on symbols representing numbers: addition, subtraction,
multiplication, division, raising to a power.
In an algebraic expression, letters can stand for numbers. When we substitute a specific value for
each variable, and then perform the operations, it's called evaluating the expression.
Example 1: Let's evaluate the expression 3y + 2y when 5 = y.
Solution: Replace each letter with its assigned value.
3(5) + 2(5) (May use parentheses!)
= 15 + 10 = 25
Example 2: Evaluate 2x3 โ x2 + y for x = 3, y = โ2
Solution: 2(3)3 โ (3)2 + (-2)
= 2(27) - 9 + (-2)
= 54 - 9 +(-2)
= 43
One of the most common expressions you'll likely need to evaluate will be polynomials. To
evaluate, you take the polynomial and plug in a value for x.
Example 3:Evaluate x4 + 3x3 โ x2 + 6 for x = โ3.
(โ3)4 + 3(โ3)3 โ (โ3)2 + 6
= 81 + 3(โ27) โ (9) + 6
= 81 โ 81 โ 9 + 6
= โ3.
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Calin M. Agut
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Calin M. Agut
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Calin M. Agut
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Calin M. Agut
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Calin M. Agut
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Calin M. Agut
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