1 / 11

8.2 Solving by Substitution

8.2 Solving by Substitution. Objective: To solve a system of equations by substituting for a variable. -3. -3. Solving by Substitution. When one variable is alone on one side of the equation, you can substitute for that variable in the other equation. x + y = 13. x = y + 3.

shaquille-charles
Download Presentation

8.2 Solving 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. 8.2 Solving by Substitution • Objective: To solve a system of equations by substituting for a variable

  2. -3 -3 Solving by Substitution • When one variable is alone on one side of the equation, you can substitute for that variable in the other equation. x + y = 13 x = y + 3 (y + 3) + y = 13 x = 5 + 3 2y + 3 = 13 x = 8 2y = 10 (8, 5) y = 5

  3. Solving by Substitution y = 3x 3x 2x + 4y = 28 y = 3( ) 2x + 4() = 28 2x + 12x = 28 y = 6 14x = 28 (2, 6) x = 2 2

  4. -2 -2 (1, 7) Solving by Substitution x + y = 8 y = 2 + 5x x + (2 + 5x)= 8 y = 2 + 5(1) 6x + 2 = 8 y = 7 6x = 6 x = 1

  5. -x -x Solving by Substitution y = x + 2 3 y = 2x - 1 y = 5 x + 2 = 2x - 1 2 = x - 1 (3, 5) 3 = x

  6. Solve for X Solve for y

  7. Parenthesis!!! -y -y (4, 1) Solving by Substitution x + y = 5 2x + 3y = 11 x = 5 - y 1 2(5 – y) + 3y = 11 x = 4 10 – 2y + 3y = 11 10 + y = 11 y = 1

  8. -39 -39 -2x -2x (5, 3) Solving by Substitution 2x + y = 13 8x + 3y = 49 8x + 3( y )= 49 13 -2x y = 13 – 2x 8x + 39 - 6x = 49 2x + 39 = 49 y = 13 – 2( x ) 5 2x = 10 y = 3 x = 5

  9. The sum of two numbers is 82. One number is 12 more than the other. What are the numbers? Let x = the larger number and y the smaller.

  10. The difference between two numbers is 9. Three times the larger number is six times the smaller. What are the numbers?

  11. Homework tonight: • Page 365 (2-26) even

More Related