direct variation y = mx (no b) lines that go through the origin y intercept of zero slope also...
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![Page 1: Direct Variation y = mx (no b) Lines that go through the origin Y intercept of zero Slope also called constant of variation (variation constant)](https://reader036.vdocuments.net/reader036/viewer/2022082713/5697bffa1a28abf838cc01ca/html5/thumbnails/1.jpg)
Direct Variation
• y = mx (no b)
• Lines that go through the origin
• Y intercept of zero
• Slope also called constant of variation (variation constant)
![Page 2: Direct Variation y = mx (no b) Lines that go through the origin Y intercept of zero Slope also called constant of variation (variation constant)](https://reader036.vdocuments.net/reader036/viewer/2022082713/5697bffa1a28abf838cc01ca/html5/thumbnails/2.jpg)
Examples of Direct Variationy = -2x y = 2x
![Page 3: Direct Variation y = mx (no b) Lines that go through the origin Y intercept of zero Slope also called constant of variation (variation constant)](https://reader036.vdocuments.net/reader036/viewer/2022082713/5697bffa1a28abf838cc01ca/html5/thumbnails/3.jpg)
Checking for Direct Variation
Graph --> is it a straight line through the origin?
Equation --> does it fit y = mx?(may need to solve for y)
![Page 4: Direct Variation y = mx (no b) Lines that go through the origin Y intercept of zero Slope also called constant of variation (variation constant)](https://reader036.vdocuments.net/reader036/viewer/2022082713/5697bffa1a28abf838cc01ca/html5/thumbnails/4.jpg)
Do these lines illustrate direct variation?
y = -1/2x x = -3
![Page 5: Direct Variation y = mx (no b) Lines that go through the origin Y intercept of zero Slope also called constant of variation (variation constant)](https://reader036.vdocuments.net/reader036/viewer/2022082713/5697bffa1a28abf838cc01ca/html5/thumbnails/5.jpg)
What is the variation constant?y = -1/2x x = -3
![Page 6: Direct Variation y = mx (no b) Lines that go through the origin Y intercept of zero Slope also called constant of variation (variation constant)](https://reader036.vdocuments.net/reader036/viewer/2022082713/5697bffa1a28abf838cc01ca/html5/thumbnails/6.jpg)
Are these equations direct variation?
y = 5x
y = -3/4x
y = -2x - 7
![Page 7: Direct Variation y = mx (no b) Lines that go through the origin Y intercept of zero Slope also called constant of variation (variation constant)](https://reader036.vdocuments.net/reader036/viewer/2022082713/5697bffa1a28abf838cc01ca/html5/thumbnails/7.jpg)
Are these equations direct variation?
y = 5x --> Yes!
y = -3/4x --> Yes!
y = -2x - 7 --> No (y-int not 0)
![Page 8: Direct Variation y = mx (no b) Lines that go through the origin Y intercept of zero Slope also called constant of variation (variation constant)](https://reader036.vdocuments.net/reader036/viewer/2022082713/5697bffa1a28abf838cc01ca/html5/thumbnails/8.jpg)
Are these equations direct variation?
2x + y = 0
-x + y = -1
4x - 5y = 0
![Page 9: Direct Variation y = mx (no b) Lines that go through the origin Y intercept of zero Slope also called constant of variation (variation constant)](https://reader036.vdocuments.net/reader036/viewer/2022082713/5697bffa1a28abf838cc01ca/html5/thumbnails/9.jpg)
Are these equations direct variation?
2x + y = 0 --> y = -2x --> YES
-x + y = -1 --> y = x - 1 --> NO
4x - 5y = 0 --> y = 4/5x --> YES
![Page 10: Direct Variation y = mx (no b) Lines that go through the origin Y intercept of zero Slope also called constant of variation (variation constant)](https://reader036.vdocuments.net/reader036/viewer/2022082713/5697bffa1a28abf838cc01ca/html5/thumbnails/10.jpg)
Online Animation
www.classzone.com
![Page 11: Direct Variation y = mx (no b) Lines that go through the origin Y intercept of zero Slope also called constant of variation (variation constant)](https://reader036.vdocuments.net/reader036/viewer/2022082713/5697bffa1a28abf838cc01ca/html5/thumbnails/11.jpg)
Homework
p256 #2-8 E,
11-22 C6,
58-62 E