Download presentation

Presentation is loading. Please wait.

Published byMagdalene Dean Modified over 6 years ago

1
Welcome back…. Let’s warm up! 1) 4x + 5y = 12 2) 3x – 2y = 12 4x + 3y = 4 4x + 2y = 2

2
8-4 Elimination Using Multiplication Objective: To solve systems of equations using the Elimination method with Multiplication **Let’s use whiteboards today!

3
Example 1 – on paper 2x + y = 5 3x – 2y = 4 7x = 14 x = 2 2(2) + y = 5 4 + y = 5 y = 1 ( ) 2= 4x + 2y = 10 3x – 2y = 4 ANSWER: (2,1)

4
On a white board!! 1) -3x – 4y = 2 -2x + y = -6 Answers: 1. (2,-2) 2. (5,-2) 3. Infinitely Many 2) 3x – 2y = 19 5x + 4y = 17 3) x – 2y = -1 -2x + 4y = 2

5
Example 2 – on paper 0 = -y + 4 y = 4 3x = 2(4) – 2 3x = 8 – 2 3x = 6 x = 2 ( ) -3= -9x = -6y + 6 9x = 5y – 2 ANSWER: (2,4) 9x = 5y – 2 3x = 2y – 2

6
EXAMPLE 3 – on whiteboard 2x – 3y = 2 5x + 4y = 28 What do we eliminate? y! 2(4) – 3y = 2 8 – 3y = 2 -3y = -6 y = 2 8x – 12y = 8 15x + 12y = 84 23x = 92 x = 4 ANSWER (4,2) ( )4 ( )3

7
EX4: 2x + 3y = 5 5x + 4y = 16 Eliminate x 1 st times 5 2 nd times -2 10x + 15y = 25 -10x – 8y = -32 7y = -7 y = -1 Eliminate y 1 st times 4 2 nd times -3 8x + 12y = 20 -15x – 12y = -48 -7x = -28 x = 4 Answer: (4,-1)

8
Try with a mathlete: 1) 3x + 5y = 11 2x + 3y = 7 2) 2x – 3y = 8 -5x + 2y = 13

9
Homework: Pg. 479 # 15 – 31 odd

10
Math Lab Systems of Equations Review **Let’s use whiteboards today!

11
Substitution 1) y = 3x x + 2y = -21 Answers: 1) (-3,-9) 2) (3,0) 2) y = 2x – 6 3x + 2y = 9

12
Elimination 1) -3x + 4y = 122) x + y = 8 3x – 6y = 18 x – y = 4 (-24,-15) (6,2)

13
Elimination with Multiplication 1) -3x – 4y = 2 -2x + y = -6 Answers: 1. (2,-2) 2. Infinitely Many 2) x – 2y = -1 -2x + 4y = 2

14
Elimination with Multiplication 1) 4x + 3y = 19 3x – 4y = 8 Answer: (4,1) 2) 4x – 7y = 10 3x + 2y = -7 Answer: (-1,-2)

15
Even More Practice Solve using any method: Shall we race?? 1) 7x + 3y = -1 4x + y = 3 2) 3x + 4y = 10 6x + 8y = 5 3) x – y = 2 2x – 3y = 5

Similar presentations

© 2022 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google