3.4 Expressions and Equations Goal: To translate phrases to algebraic expressions (emphasizing grouping symbols) To solve problems by writing and solving equations 3.4 Expressions and Equations

Technique Underline key phrases and write what they mean underneath Then put it all together

Key Words: What words mean addition? What words mean subtraction? What words mean multiplication? What words mean division?

Review: Write an expression that means: 5 more than a number “n” n + 5

Review: Write an expression that means: 9 less than a number “n”

5 times the sum of a number and 5 Words that means a grouping symbol: “the sum of” “the difference of” “the quantity” “the product of” “the quotient of” 5 times the quotient of a number and 5

5 times the quantity 3 less than a number. Remember: with less than we write the expression backwards… NOT left to right. 5(n – 3)

14 less than the product of 3 and a # Remember: with less than we write the expression backwards… NOT left to right. (3n) - 14

4 times the quantity 3 greater than a number

One-half the difference of a number and 1

Two fewer than the product of 10 and a number

The quarterback completed 8 more than half of the passes he attempted The quarterback completed 8 more than half of the passes he attempted. Let p = the number of passes attempted. Write an expression for the number of passes completed. Completed = 8 more than half of “p”

Word Problems Read the problem a few times Underline key phrases and translate the english into math Write down what you know Identify what you are trying to find Translate into an equation Solve Check

Arthur is two years younger than Chan. Arthur is 21. How old is Chan? = 2 21 Arthur is two years younger than Chan. Arthur is 21. How old is Chan? Let c = the age of Chan. 21 = c - 2 23 = c

The number of salted peanuts in a nut mix is 13 times the number of cashews. There are 52 salted peanuts. How many cashews are there? = Let c = number of cashews 52 = 13 • c 4 = c

Nora divided 315 cans equally among 26 cartons and had 3 cans left over. How many cans were in each carton? Let x = cans per carton (cans per carton)(# cartons) = total cans + 3 26x + 3 = 315

Let x = points on first test The final exam had three times as many points as the first test, plus a bonus question worth 25 points. The final exam was worth 160 points (including the bonus). How many points was the first test worth? Let x = points on first test Final = 3 times first test plus bonus 160 = 3x + 25

Child dinner = x - 3 4 • Child dinner = $18 At Max's Restaurant the cost of a child's dinner is $3.00 less than the cost of an adult dinner. You bought four children's dinners and paid $18.00. Find the cost of an adult dinner. “x” Child dinner = x - 3 4 • Child dinner = $18 4(x – 3) = 18

Assignment: Page 133 # 2-16 , 22-25 all