TechMathII - 2.1 - Variables and Expressions
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Transcript of TechMathII - 2.1 - Variables and Expressions
Bell RingerBell Ringer
Solve the following for x = -2 and y = 4Solve the following for x = -2 and y = 4
1.1. 2x – 82x – 8
2.2. 3x + y3x + y
3.3. -2x +4y – 8-2x +4y – 8
4.4. ½ y – 5x + 15½ y – 5x + 15
5.5. 2x + 5y2x + 5y 2 2
Please Excuse My Dear Aunt Sally!Please Excuse My Dear Aunt Sally!“Order of Operations”“Order of Operations”
ParenthesisParenthesis
ExponentsExponents
MultiplicationMultiplication
DivisionDivision
AdditionAddition
SubtractionSubtraction
ExamplesExamplesSolve using the Order of OperationsSolve using the Order of Operations
1) 2 + 5 * 41) 2 + 5 * 4
2) 3 * 2 - 82) 3 * 2 - 822
3) 2 * 27 – 13 * 23) 2 * 27 – 13 * 2
4) 4 * (8 – 2 * 3)4) 4 * (8 – 2 * 3)
5) 5) 18 (3 + 4)18 (3 + 4)
3 + 83 + 8
You try!You try!Solve using the Order of OperationsSolve using the Order of Operations
1) 4 + 6 * 81) 4 + 6 * 8
2) 40 / 5 * 22) 40 / 5 * 2
3) 4 + 3 ( 15 – 23) 4 + 3 ( 15 – 233))
4) 4) 2(3 + 4)2(3 + 4)
77
ExamplesExamplesEvaluate each expression for a = 2 and b = 3.Evaluate each expression for a = 2 and b = 3.
6) 6) a + 2ba + 2b
55
7) 7) 5a + b5a + b
33
8) a + 3b8) a + 3b22
9) 7a – 4(b + 2)9) 7a – 4(b + 2)
You try 2!You try 2!
Evaluate each expression for a = 3 and b = 5.Evaluate each expression for a = 3 and b = 5.
1) 3a – b1) 3a – b22
2) 2) a – 9ba – 9b 2a 2a
3) 4a – 9b3) 4a – 9b22
4) 4) 4 – 2a4 – 2a 3b3b
Homework
Order of Operations WS
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Evaluate each expression for a = 5 and b = 8.Evaluate each expression for a = 5 and b = 8.
1) 2a – 3b1) 2a – 3b22
2) 2) a – 4ba – 4b 3a 3a
3) 2a – 4b3) 2a – 4b22
4) 4) 5 – 7a5 – 7a 4b4b
VocabularyVocabularyVariable Variable – a symbol (or a letter) that represents – a symbol (or a letter) that represents
an unknown number an unknown number
Algebraic ExpressionAlgebraic Expression – mathematical phrase – mathematical phrase that that can include numbers, variables, and can include numbers, variables, and
operation symbolsoperation symbols
EquationEquation – mathematical sentence that uses an – mathematical sentence that uses an equal sign equal sign
ConstantsConstants – numbers – numbers
ExamplesExamples
Write an algebraic expression for each phrase.Write an algebraic expression for each phrase.
1) 6 more than 1) 6 more than kk
2) 2) y y minus 5minus 5
3) the quotient of h and 203) the quotient of h and 20
4) the sum of 8 times 4) the sum of 8 times 2 2 and and tt
You try!You try!
Write an algebraic expression for each phrase.Write an algebraic expression for each phrase.
1) 7 minus x1) 7 minus x
2) 12 more than y2) 12 more than y
3) the sum of x times 3 and r3) the sum of x times 3 and r
4) the quotient of 9 and w4) the quotient of 9 and w
ExamplesExamples
Define a variable and write an expression for each Define a variable and write an expression for each phrase.phrase.
5) 8 less than a number5) 8 less than a number
6) a number divided by 86) a number divided by 8
7) 7 more than twice a number 7) 7 more than twice a number
8) 6 times the sum of w and 9 8) 6 times the sum of w and 9
You try 2!You try 2!
Define a variable and write an expression for each Define a variable and write an expression for each phrase.phrase.
1) A number plus negative nine1) A number plus negative nine
2) The product of 12 and a number2) The product of 12 and a number
3) Eight more than three times a number3) Eight more than three times a number
4) Three times the sum of two numbers4) Three times the sum of two numbers
ExamplesExamplesDefine a variable and write an equation for each Define a variable and write an equation for each phrase.phrase.
9) The weight of a truck is two times the 9) The weight of a truck is two times the weight of a car.weight of a car.
10) The number of gallons of water used to 10) The number of gallons of water used to water trees is 30 times the number of trees.water trees is 30 times the number of trees.
11) The number of pieces of pizza 11) The number of pieces of pizza remaining from an 8-slice pizza after you remaining from an 8-slice pizza after you have eaten some pieces. have eaten some pieces.
HomeworkHomework