Evaluating+Algebraic+Expressions+-+Luke

// Evaluating Expressions & Applying Rules Chapter Review //

** Evaluating Expression ** Evaluating is when you substitute a number for each expression to work out the value. For example If x=4,3x=3X4 =12 So if x=4 then the question 3x means 3X4 Because the 4 replaces the x and then you times them and get your answer(12). 3x=3X4=12

Now doing questions which involves two letters are like the same but you replace two letters instead. Such as:Given a=3 and b=5 evaluate each of the following:a/4b=3/4x5 =2/12 =1/6 Replace the following letter with the number given Then halve if possible 5a+b= =5xa+b =5x3+5 =20 Replace the letters with the numbers given Then do the question Now doing questions that has brackets in them: Given x=2 y=6 =5(x+y) =5(2+6) =5(8)=40  Replace letters with numbers given add numbers inside brackets times the outside number and the bracket number 2(6x+7y) =2(6x2+7x6) =2(12+42) =2(54)  =108  Replace x & y into the number given Times the numbers inside brackets Add togeather Then times the outside number with the bracket number

Applying Rules

Pronumerals are often used to write rules to show how different variables are related. The perimeter of a rectangle is given by the rule P=6L where P is the perimeter and L is the side length of the rectangle. Find the perimeter of a square of side length 3cm. P=6L  P=6x3   =18   Therefore the perimeter is 18cm. Q A)Define the variables Q B) Write a rule for the cost of hiring the tennis court for any number of hours.Q C) Use your rule to find the cost of hiring the basketball court for 2 hours.   A) The cost of hiring a basketball court is made up of two parts: a fixed charge of $8 plus $4 per hour. Let C be the cost of hiring the basketball court and h the number of hours the court is hired for. B) C=8+(4xh)  =8+4h   C) C=8+(4x2)   =8+8   =16 Cost of hiring the basketball court for 2 hours is $16 The variables are the cost of hiring the basketball court and the number of hours for which the court is hired. Cost=fixed charge of $8  + ($4x number of hours)   Replace the h with 2 in the formula c=7+5h Question Time Given a=3 1)a+5 2)3a 3)12/a 4)a+9 5)9-a 6)9a 7)a+3 8)7+a 9)6a 10)14 Given x=5 & y=2

11)2(x+y) 12)2(4x-y) 13)2(x-y) 14)5(x+2y) 15)3(2x+y)

Answers 1)8 2)9 3)15 4)12 5)6 6)27 7)6 8)10 9)18 10)15  11)14 12)36 13)6 14)45 15)36