1.2 Variables, Expressions, and Properties
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Transcript of 1.2 Variables, Expressions, and Properties
1.2 Variables, Expressions, and Properties
Vocabulary• Variable: A symbol, usually a letter, used to represent a number.
• Algebra: Branch of mathematics that involves expressions with variables.
• Algebraic Expression: It contains a variable, a number, and at least one operation. Example, 4n
• Evaluate: Find the value of an algebraic expression, first replace the variable or variables with the known values
• Numerical Expression: One with only numbers and operations
• Counterexample: Opposite
• Property: A feature of an object or a rule that is always true.
Order of Operations (PEMDAS)• Parenthesis first. Start with the innermost
grouping.
• Exponents. (5²)
• Multiply
• Divide from left to right
• Add
• Subtract from left to right
Properties
• Commutative: Applies ONLY to addition and multiplication. Examples, 2+1=3 as 1+2=3; 2*8=16 and 8*2=16
• Associative: Applies ONLY to addition and multiplication. Examples 2+(3+8)=(2+3)+8; as 3*(4*5)=(3*4)*5
• Distributive: The word says it all DISTRIBUTE. Example, 4(6+2)=4*6+4*2
• Identity: Something that does not affect the original number. Example,9+0=9, 5*1=5
Identify PropertiesName the property
1) 2*(5*n)=(2*5)*n
2) 42+x+8=42+8+x
3) 3x+0=3x
4) 3(2+5)=3(2)+3(5)
5) 6(5*2)=(6*5)2
Evaluate Algebraic Expressions• A= 5 and B= 4
4a-3b+1
• G=5g²-2g-4
• C=3 and d=76c+4-3d
4(d-c)+1
d²+5d-6
Evaluate Algebraic Fractions• M=9 and n=5
4+6m2n-8
• P=5 and q=123p-68-p
• P=5 and q=124q
Q+2(p=1)
q²4p-2