1 / 9

Solving Systems of Equations The Method of Elimination

Solving Systems of Equations The Method of Elimination. Hi Class, Sorry I’m not there, but my son is sick. Try your best to follow and copy these slides. This is a new method for finding the Point of Intersection (POI). Solving by Elimination Example: 2x + y = 10 and 4x + y = 2.

braith
Download Presentation

Solving Systems of Equations The Method of Elimination

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 Systems of Equations The Method of Elimination

  2. Hi Class, Sorry I’m not there, but my son is sick. Try your best to follow and copy these slides. This is a new method for finding the Point of Intersection (POI)

  3. Solving by Elimination Example: 2x + y = 10 and 4x + y = 2 Step 1: Line up the equations on top of each other and draw a line underneath. 2x + y = 10 Step 2 – Choose to add or subtract the 2 equations. *The point is to eliminate (get rid of) the x’s or the y ‘s. 4x + y = 2 So, it makes sense to SUBTRACT these equations and eliminate the y’s. Note: If you added the equations, neither the x’s or the y’s would disappear. So……

  4. So….place a subtraction sign in front of the second equation and subtract the x’s and the y’s 2x + y = 10 -- 4x + y = 2 -2x = 8 x = 8/-2 x = -4 Now, divide both sides by -2 to isolate x Next….find y (substitute x = -4 back into one of the original equations) 2x + y = 10 2(-4) + y = 10 -8 + y = 10 y = 10 + 8 y = 18 Therefore the POI is (- 4, 18)

  5. X + 2y = 2 X – 2y = 4 __ Should we add or subtract? **YOU have to CHOOSE the x or y to eliminate. If we choose the x’s to eliminate, then we should subtract 4y = -2 Y = -0.5 Now find x by substituting y=-0.5 into either of the first two equations. X + 2(-0.5) = 2 X –1 = 2 X = 3 The solution is (3, -0.5)

  6. x + y = 1/2 2x – y = 5/2 + Should we add or subtract? **Note: if we subtract, nothing would be eliminated 3x = 3 x = 1 Now find y by substituting x=1 into either of the first two equations. x + y =1/2 1 + y = ½ y = ½ -1 y= -0.5 The solution is (1, -0.5)

  7. x + y = 3 x – y = 7 __ Should we add or subtract? Again: YOU CHOOSE the x or y to eliminate. In this question I chose to eliminate x. Soooo……I have to SUBTRACT 2y = -4 y = -2 Now find x by substituting y=-2 into either of the first two equations. x + y = 3 x + (-2) = 3 x –2 = 3 x = 3 + 2 x = 5 The solution is (5, -2)

  8. x - y =1 2x + y = 5 + Should we add or subtract? 3x = 6 x = 2 Now find y by substituting x = 2 into either of the first two equations. x – y = 1 2 – y = 1 -y = 1 - 2 -y = -1 y = -1 The solution is (2, 1)

  9. Homework Handout: The Elimination Method (Day 1)

More Related