Presentation on theme: "Chapter 1 Lesson 1 Variables and Expressions"— Presentation transcript:
1 Chapter 1 Lesson 1 Variables and Expressions Objective:Evaluate expressions containing variables and translate verbal phrases into algebraic expressions.
2 Operation Vocabulary – What Each Sign Means +-xplussummore thanincreased bytotalin allminusdifferenceless thansubtractdecreased bytimesproductmultipliedeachofdividedquotient
3 Examples Translate each phrase into an algebraic expression. a number decreased by eightLet n represent the number.The words ‘decreased by’ suggests subtraction.The algebraic expression is n – 8.b. seven more than twice as many dollars.Let d represent dollars.The words ‘more than’ suggest addition and the word twiceis another way of saying ‘two times’.The algebraic expression is 7 + 2d or 2d + 7
4 Examples Translate each phrase into an algebraic expression. c. a number increased by eightLet b represent the number.The words ‘increased by’ suggests addition.The algebraic expression is b + 8.d. 15 plus the quotient of 20 and x.The word ‘plus’ means addition.The words ‘quotient’ suggest divide.The algebraic expression is /x or 20/x + 15
5 Examples Translate each algebraic expression into a phrase. e. 7h Two things beside each other mean multiply.Answer: seven times h or seven multiplied by hf. 5 - xWhat you have to be careful about here is that you get yourwords in the right order. Are you subtracting 5 from x orx from 5? Whatever is second is being subtracted from the first.Answer: x subtracted from 53m + 2Answer: two added to three times m ORtwo more than three times m ORthree times m plus 2There are several different ways to write this!
6 A Little Harder…Draw a picture representing a rectangle whose length iseight less than four times its width. Write an expressionfor the perimeter of the rectangle.We know something about the length but have no clue about width, so…width is our variable.Eight less than means subtract. Four times means multiply. So subtract eight FROM four times.Now, how do you find perimeter?Add up all the sides!w + w + 4w – 8 + 4w – 8Do you remember how to combine like terms?10w - 16w4w - 8