1 / 5

Solving Algebraically by Substitution

Solving Algebraically by Substitution. Look for an isolated variable or one that is easy to isolate. Then plug in to other equation. y = -½x – 7 2x – 6y = 12. 2x – 6 (-½x – 7) = 12 . 2x + 3x + 42 = 12. y = -½x – 7 . 5x = - 30. y = -½ (-6) – 7 . x = - 6. y = 3 – 7 . (-6, - 4).

phallon
Télécharger la présentation

Solving Algebraically by Substitution

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 Algebraically by Substitution Look for an isolated variable or one that is easy to isolate. Then plug in to other equation. y = -½x – 7 2x – 6y = 12 2x – 6 (-½x – 7) = 12 2x + 3x + 42 = 12 y = -½x – 7 5x = - 30 y = -½(-6) – 7 x = - 6 y = 3 – 7 (-6, - 4) y = - 4

  2. Solving Algebraically by Elimination I sure do love that trusty substitution! Look for a pair of matching opposites x + 3y = 8 6x – 3y = 27 + 7x = 35 7 7 But sometimes there’s an easier way! x + 3y = 8 x = 5 5 + 3y = 8 (5, 1) 3y = 3 y = 1

  3. Anyway, where were we? If you don’t have matching opposites, you can make them match. 4( ) 2x + y = 3 7x – 4y = 18 8x + 4y = 12 7x – 4y = 18 Find an LCM to distribute

  4. Steps to Solving by Elimination Look for equal opposites or a pair that’s easy to manipulate Step 1 Distribute the coefficient you need across one or both equations to make equal opposites Step2 Add equations together and cancel pair Step3 Step4 Solve for one variable Plug answer back in to find other variable Step5

  5. Practice 3x + 4y = 1 2x + 4y = 6 3x + 2y = -1 4x – 5y = -32 (-5, 4) (-3, 4)

More Related