Algebraic Expressions Lesson 1-2 Algebraic Expressions

Variable – a symbol, usually a letter, that represents one or more numbers. Algebraic expression (variable expression) – an expression that contains one or more variables. Evaluate – when you substitute numbers in for variables and follow the order of operations to solve the problem.

Evaluate a – 2b + ab for a = 3 and b = -1

Term – part of an algebraic expression that is being added Term – part of an algebraic expression that is being added. It can be a number, a variable, or the product of a number and one or more variables. Coefficient – numerical factor in a term Like terms have the same variables raised to the same power.

3x2 and -7x2 are like terms 5x2y3 and 9x3y2 are not like terms To combine like terms add or subtract their coefficients

Definition of Subtraction a – b = a + (-b) Definition of Division a / b = a ∙ 1/b , b ≠ 0 Distributive Prop. for Subtraction a(b – c) = ab – ac Mult. By 0 0 ∙ a = 0 Mult. By -1 –1 ∙ a = –a Opposite of a sum –(a + b) = –a + (–b) Opposite of a difference –(a – b) = b – a Opposite of a product –(ab) = –a ∙ b = a ∙ (–b) Opposite of an opposite –(–a) = a

Examples Evaluate each expression for c = -3 and d = 5 c(3 – d) – c2 Combine like terms 2x2 + 5x – 4x2 + x – x2

 

Assignment: 2 – 46ab, even 68-70 on pg 15-16