1 / 15

Solving Equations using Addition and Subtraction

Learn how to solve equations by isolating the variable using addition and subtraction. Practice with examples and check your answers.

gkahn
Télécharger la présentation

Solving Equations using Addition and Subtraction

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. Section 3.1 Solving Equations Using Addition and Subtraction.

  2. To Solve an Equation means... To isolate the variable having a coefficient of 1 on one side of the equation. Ex: x = 5 is solved for x. y = 2x - 1 is solved for y.

  3. r + 16 = -7 Here is an example…1) Solve r + 16 = -7 Think of this equation as a balance scale. Whatever you do to one side has to be done to the other to keep it balanced!

  4. 1) Solve r + 16 = -7 To solve, you must get the variable by itself!! What is the variable? What number is on the same side as r? +16 To get r by itself, we must undo the “add 16”.What is the opposite of addition? Subtract 16

  5. 1) Solve r + 16 = -7 - 16 -16 r = -23 -23 + 16 = -7 • Draw a line to separate the equation into 2 sides • Subtract 16 from both sides • Simplify vertically • Check your answer by substituting your answer back into the problem

  6. Answer Now 2) Solve x + 2 = -3Get the variable by itself. What is your first step? • Add 2 to both sides • Subtract 2 from both sides • Add 3 to both sides • Subtract 3 from both sides

  7. 2) Solve x + 2 = -3 - 2 - 2 x = -5 -5 + 2 = -3 • Draw a line to separate the equation into 2 sides • Subtract 2 from both sides • Simplify vertically • Check your answer by substituting your answer back into the problem On homework and tests, be sure to check your work!! There is no reason why you should miss a problem!

  8. Answer Now 3) Solve 8 = m - 3 • m = 5 • m = 11 • m = 24 • m = 8/3

  9. 3) Solve 8 = m - 3 + 3 + 3 11= m 8 = 11 - 3 • Draw a line to separate the equation into 2 sides • Add 3 to both sides • Simplify vertically • Check your answer by substituting your answer back into the problem

  10. REMEMBER: When solving equations, we want to eliminate double signs. Example 1 y + (-3) = 8 is rewritten as y – 3 = 8 p – (-5) = 6 is rewritten as p + 5 = 6 Example 2 As a general rule, replace “+ (- )” with “–” and “– (- )” with “+”. This will make things less confusing in the future!

  11. 4) Solve y + (-3) = 7 y – 3 = 7 + 3 +3 y = 10 10 + (-3) = 7 • Draw a line to separate the equation into 2 sides • Eliminate the double sign • Add 3 to both sides • Simplify vertically • Check your answer by substituting your answer back into the problem

  12. 5) Solve. x - (-2) = 1 • Draw a line to separate the equation into 2 sides • Eliminate the double sign • Subtract 2 from both sides • Simplify vertically • We haven’t gotten x by itself. If we read this aloud, it is “the opposite of x equals -1”. What would x be equal? • Check your answer x + 2 = 1 - 2 - 2 x = -1 x = -1 (-1) + 2 = 1

  13. Answer Now Solve y – (-3) = 7 • y = 10 • y = 4 • y = -10 • y = -4

  14. Homework: 9/9/13 Workbook page 13 Solving Equations by Adding or Subtracting

More Related