HELLO!!!!• Hopefully you were all so nice to the sub and

smiled pretty. The video is having issues uploading so I have put the full notes I walk through on the video here. Please follow along click by click and take your own notes on the Notes file (print it out and use a pencil). The assignment we are doing is listed on the Unit 2 calendar if you want to be cool and do more math tonight.

• The video is up and working on YouTube. Search KimSwindell and choose the substitution vide

• See you tomorrow (or today if you are a procrastinator)

• Again… DO NOT print this pp document. I will throw it away. Take your own notes.

SubstitutionExample 1 Steps

1. Solve one equation for x or y

2. Substitute your new equation into the other equation

3. Solve

4. Plug your answer into the equation you wrote in #1 and solve

5. CHECK!!!

33

552

yx

yx

yx 33

2(3 – 3y) + 5y = –5

6 – 6y + 5y = –5

6 – y = –5

–y = –11

y = 11

x = 3 – 3(11)

x = 3 – 33

x = -30 (-30, 11)

2(-30) + 5(11) = -5

-30 + 3(11) = 3

SubstitutionExample 2

863

42

yx

yx

3(2y + 4) – 6y = 8

6y + 12 – 6y = 8

12 = 8

No Solution

so

Steps1. Solve one equation for

x or y

2. Substitute your new equation into the other equation

3. Solve

42 yx

SubstitutionExample 3 Steps

1. Solve one equation for x or y

2. Substitute your new equation into the other equation

3. Solve

34

9312

yx

yxxy 43

12x – 3(3 + 4x) = – 9

12x – 9 – 12x = – 9

– 9 = – 9

Infinite Solutions

so