1 / 10

Solving Equations by Adding or Subtracting

Solving Equations by Adding or Subtracting. PRE-ALGEBRA LESSON 2-5. (For help, go to Lesson 2-1.). Bell Work # 9. Simplify each expression. 1. 3 + 4 – 4 2. 7 + 9 – 7 3. 8 – 2 + 2 4. 6 + 2 – 2. Check Skills You’ll Need. 2-5. Solving Equations by Adding or Subtracting.

rleija
Télécharger la présentation

Solving Equations by Adding or Subtracting

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Solving Equations by Adding or Subtracting PRE-ALGEBRA LESSON 2-5 (For help, go to Lesson 2-1.) Bell Work # 9 Simplify each expression. 1. 3 + 4 – 4 2. 7 + 9 – 7 3. 8 – 2 + 2 4. 6 + 2 – 2 Check Skills You’ll Need 2-5

  2. Solving Equations by Adding or Subtracting PRE-ALGEBRA LESSON 2-5 Solutions 1. 3 + 4 – 4 2. 7 + 9 – 7 = 3 + (4 – 4) = 9 + (7 – 7) = 3 + 0 = 9 + 0 = 3 = 9 3. 8 – 2 + 2 4. 6 + 2 – 2 = 8 + (2 – 2) = 6 + (2 – 2) = 8 + 0 = 6 + 0 = 8 = 6 2-5

  3. Solving Equations by Adding or Subtracting PRE-ALGEBRA LESSON 2-5 Vocabulary Vocabulary and Concepts Subtraction Property of Equality You can subtract the same number from each side of an equation Arithmetic Algebra • = 2( 5 ) if a = b 5 c 10 – 5 = 2( 5 ) - _____ then a – c = b - _____ Quick Check 2-5

  4. Solving Equations by Adding or Subtracting PRE-ALGEBRA LESSON 2-5 Vocabulary Addition Property of Equality You can add the same number from each side of an equation Arithmetic Algebra 8 = 2( 4 ) if a = b 3 c 8 + 3 = 2( 4 ) + _____ then a + c = b + _____ Inverse Operations ____________________ are operations that undo each other Quick Check 2-5

  5. y + 5 = 13 Subtract 5 y + 5 – 5 = 13 – 5from each side. – 5 = – 5 Check y + 5 = 13 8 + 5 13 Replace y with 8. 13 = 13 Solving Equations by Adding or Subtracting PRE-ALGEBRA LESSON 2-5 Solve y + 5 = 13. Method 1 Method 2 y + 5 = 13 y = 8 Simplify. y = 8 Quick Check 2-5

  6. Words target number is 250 plus number to buy Let x = number to buy. 327 = 250 + x Equation Solving Equations by Adding or Subtracting PRE-ALGEBRA LESSON 2-5 Larissa wants to increase the number of books in her collection to 327 books. She has 250 books now. Find the number of books she needs to buy. 2-5

  7. Check  Is the answer reasonable? 250 plus the number of books bought should be a total collection of 327. 250 + 77 = 327 Solving Equations by Adding or Subtracting PRE-ALGEBRA LESSON 2-5 (continued) 327 = 250 + x 327 = x + 250 Use the Commutative Property of Addition. 327 – 250 = x + 250 – 250Subtract 250 from each side. 77 = xSimplify. Larissa needs to buy 77 more books. Quick Check 2-5

  8. Solving Equations by Adding or Subtracting PRE-ALGEBRA LESSON 2-5 Solve c – 23 = – 40. c – 23 = – 40 c – 23 + 23 = – 40 + 23Add 23 to each side. c = –17 Simplify. Quick Check 2-5

  9. Words cost of CD player was $113 less than cost of DVD player t Let = cost of the DVD player. Equation 80 = t – 110 Solving Equations by Adding or Subtracting PRE-ALGEBRA LESSON 2-5 Marcy’s CD player cost $113 less than her DVD player. Her CD player cost $78. How much did her DVD player cost? 80 = t – 110 80 + 110 = t – 110 + 110 Add 110 to each side. 190 = tSimplify. Marcy’s DVD player cost $190. Quick Check 2-5

  10. Solving Equations by Adding or Subtracting PRE-ALGEBRA LESSON 2-5 Solve each equation. 1.y + 8 = 12 2. 7 + f – 21 = –20 3. 67 = g – (–36) 4. Ricky rides his bike 12 miles every day. He stops after 7 miles to rest. How much farther does he have to ride? 4 –6 31 5 mi 2-5

More Related