1 / 13

Solving Multi-Step Equations

Solving Multi-Step Equations. 4.3 Learn to solve multi step equations so you can solve real world problems such as finding when one thing catches another (runner, cars). Steps. To solve this type of equation you have to get variables on the same side of equation

tejano
Download Presentation

Solving Multi-Step Equations

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 Multi-Step Equations 4.3 Learn to solve multi step equations so you can solve real world problems such as finding when one thing catches another (runner, cars)

  2. Steps • To solve this type of equation you have to get variables on the same side of equation • Remember to solve we do reverse PEMDAS

  3. 4x = 2x -9 Subtract 2x from each side 2x = -9 Divide by 2 X = -9/2 14c + 8 = 9c – 17 Subtract 9c from both sides 5c + 8 = -17 Subtract 8 from both sides 5c = -25 Divide both sides by 5 c = -5 Example I

  4. Example II • A discount store charges $11 per cd. A CD club gives members 8 free CD’s then charges $15 per CD. When does the cost at the discount store equal the cost of the CD club? • What should we do first?

  5. Define the variable! • Let x = ? • X = the number of CD’s we buy • Write two equations, one for the discount store and one for the CD club • Discount Store = 11x • CD club = 15(x-8) …. • Careful this does not count for first 8 CD’s

  6. The equation asks when the costs are equal… What do we do next? • Let’s set them equal to each other so… • 11x = 15(x-8) • 11x = 15x – 120 (distributive property) • 11x – 15x = -120 (get x terms to one side) • -4x = -120 (divide both sides by -4) • x = 30

  7. Example III • Al is a sprinter on a track team. He can run at a rate of 9m/s. His brother Bill can run only run 6 m/s so Al gives him a 25m head start in a 100m race. • A)After how many seconds will Al catch Bill? • B) How far will they be from the starting line when Al catches Bill?

  8. A • To find out when the distances are equal write and solve an equation. • Al’s distance = Bill’s distance • Let t = # of seconds • 9t = 25 + 6t • Subtract 6t from both sides • 3t = 25 ( divide by 3) • t = 25/3 or about 8.333 • So Al catches Bill after 8.3 seconds

  9. B • Al’s distance is 9t • We plug in 25/3 or 8.3 in for t because that is the time it takes for Al to catch him. • So we get 9 * (25/3) • = 75 • Therefore Al catches Bill when they are 75m from the starting line

  10. Homework • p. 162 #1-19

  11. 7x-4 = 7(x-4) 7x-4=7x-28 7x-4-7x=7x-28-7x -4 = -28 This statement is never true 8x -12 = 2x +2(3x-6) 8x – 12 = 2x+ 6x -12 8x -12 = 8x – 12 This statement is always true and is an identity Identity Sometimes an equation has no solution, because no value of the variable will make the equation true. Sometimes all numbers are solutions of an equation. An equation with all numbers as its solution is called an identity.

  12. Try These • 2x – 9 = 4x - 2(x) + 9 • 4x = -4x • -3x + x = 2 (-x) • 3 = 3 • 9= 9x

  13. Homework • P. 163 #25-34 not 33 • P. 164 #37-40 • P. 164 #1-10e Access your progress

More Related