3-4 Expressions and Equations Warm-up Problems Write an algebraic expression for each of the following. 1.Twice the number n 2.Half of the number n 3.5 more than a number Translate to an equation and solve. 4.Arthur is two years younger than Chan. Arthur is 21. How old is Chan? 5.The number of salted peanuts in a nut mix is 13 times the number of cashews. There are 52 peanuts. How many cashews are there?

Chapter Expressions and Equations

Examples 1, 2, & times the quantity 3 less than a number 2.½ the sum of a number and less than the product of 3 and a number

Try This Write as an algebraic expression. a.3 less than twice a number b.½ the difference of a number and 1 c.4 times the quantity 3 greater than a number d.2 fewer than the product of 10 and a number

Example 4 Jason’s weekly salary is $35 less than twice David’s weekly salary. Let D = David’s weekly salary in dollars. Write an expression, using D, for Jason’s weekly salary. David’s weekly salary = D Jason’s weekly salary = 2D - 35

Try This e.This year Todd sold five fewer houses than twice as many as he sold last year. Let n = the number he sold last year. Write an expression for the number of houses that Todd sold this year. f.Ellen Ikeda scored two points more than half the number scored by the whole team. Let t = the number of points scored by the whole team. Write an expression for the number of points Ellen scored.

Example 5 The number of girls in the band is 6 more than twice the number of boys. There are 88 girls in the band. How many boys are in the band? let b = the number of boys in the band 2b + 6 = the number of girls in the band 2b + 6 = 88 –6 –6 2b = 82

Try This g.When Jill sells two more buckets, she will have sold 3 times as many buckets as Jack sold. Jill has sold 19 buckets. How many buckets has Jack sold? h.An 18-mile section of highway is being paved. The first 3 miles are done. The same number of miles will be paved each day. How many miles should be paved each day to complete this section in the next 10 days?