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# คาบ 2

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### คาบ 2

1. 1. Graphing Linear Equations in One Variable<br />
2. 2. What do each of these ordered pairs have in common?<br />(4, -3)<br />(4, -2)<br />(4, -1)<br />(4, 0)<br />(4, 1)<br />(4, 2)<br />(4, 3)<br />(4, 4)<br />(4, 5)<br />The x-coordinate is always the same. The y-coordinate varies.<br />Graph each point on the same coordinate plane.<br />
3. 3. The equation that represents this relationship between x and y is x = 4.<br />The graph of x = 4 is a VERTICAL LINE that crosses the x-axis at 4. All the points of this line (and no other points) have an x-coordinate of 4.<br />y<br />x<br />Notice that the equation doesn’t have a y variable. The equation will never intersect the y-axis.<br />
4. 4. What do each of these ordered pairs have in common?<br />(-4, -1) <br />(-3, -1) <br />(-2, -1) <br />(-1, -1) <br />(0, -1) <br />(1, -1) <br />(2, -1) <br />(3, -1) <br />(4, -1) <br />The y-coordinate is always the same; the x-coordinate varies.<br />
5. 5. Notice that the equation doesn’t have an x variable. The equation will never intersect the x-axis.<br />y<br />The equation that represents this relationship between x and y is y = -1.<br />The graph of y = -1 is a HORIZONTAL LINE that crosses the y-axis at -1. All the points of this line (and no other points) have y- coordinate of -1.<br />x<br />
6. 6. Sketching Horizontal and Vertical Lines<br />Sketch the graph of x = 2.<br />y<br />The equation does not have y as a variable. The equation says that the x-coordinate will always be 2, regardless of the value of y.<br />x<br />To graph the equation, put a dot on the x-axis at 2. There is no y-coordinate in the equation, so the equation of this line will never cross the y-axis.<br />
7. 7. Sketching Horizontal and Vertical Lines<br />Sketch the graph of y = -3.<br />y<br />The equation does not have x as a variable. The equation says that the y-coordinate will always be -3, regardless of the value of x.<br />x<br />To graph the equation, put a dot on the y-axis at -3. There is no x-coordinate in the equation, so the equation of this line will never cross the x-axis.<br />
8. 8. Sketch the graphs of x = 7 and y = -4. Find the point of intersection of the two graphs.<br />y<br />Graph x = 7. Plot a point on the x-axis at 7. The equation has no y-value, so the line will never cross the y-axis.<br />x<br />Graph y = -4. Plot a point on the y-axis at -4. The equation has no x-value, so the line will never cross the x-axis.<br />(7, -4)<br />
9. 9. Sketch the graphs of x = -4 and y = -1. Find the point of intersection of the two graphs.<br />y<br />Graph x = -4. Plot a point on the x-axis at -4. The equation has no y-value, so the line will never cross the y-axis.<br />x<br />Graph y = -1. Plot a point on the y-axis at -1. The equation has no x-value, so the line will never cross the x-axis.<br />(-4, -1)<br />
10. 10. Write equations for the horizontal line and the vertical line that pass through the point (-7, -3)<br />Plot the point (-7, -3).<br />Graph a vertical line through the point. The line intersects the x-axis at -7. It never intersects the y-axis. What is its equation?<br />y<br />x = -7<br />x<br />Graph a horizontal line through the point. The line intersects the y-axis at -3. It never intersects the x-axis. What is its equation?<br />y = -3<br />
11. 11. Home work<br />1. Write equations for the horizontal line and the vertical line that pass through the point (-9, 4)<br />2. Write equations for the horizontal line and the vertical line that pass through the point (6, 7)<br />3. Write equations for the horizontal line and the vertical line that pass through the point (-5, 8)<br />4. Write equations for the horizontal line and the vertical line that pass through the point (10, -2)<br />5. Write equations for the horizontal line and the vertical line that pass through the point (100, -50)<br />
12. 12. 1. Write equations for the horizontal line and the vertical line that pass through the point (-9, 4)<br />y<br />x = -9<br />x<br />y = 4<br />
13. 13. 2. Write equations for the horizontal line and the vertical line that pass through the point (6, 7)<br />y<br />y = 7<br />x = 6<br />x<br />
14. 14. 3. Write equations for the horizontal line and the vertical line that pass through the point (-5, 8)<br />y<br />y = 8<br />x = -5<br />x<br />
15. 15. 5. Write equations for the horizontal line and the vertical line that pass through the point (100, -50)<br />50<br />40<br />30<br />20<br />10<br />x<br />-10<br />y = -50<br />-20<br />-30<br />-40<br />-50<br />-60<br />x = 100<br />-70<br />20<br />10<br />30<br />40<br />50<br />y<br />