Download - Lines
Lines y
xO 2 4 6
2
4
6
–6
–4
–2–6 –4 –2
How do you graph the line and find its equation when
1. You are given the y-intercept and the slope.
Example: y-intercept is 1 and slope is 2/3. Equation:
2. You are given a point and the slope.
Example: point is (–2, 3) and slope is –3. Equation:
3. You are given two points.
Example: 1st point is (3, –4) and 2nd point is (2, 1). Equation:
Slope-Intercept Form:
where m is the slope and b is the y-intercept
Example:
y = x – 3
Point-Slope Form:
where (x1, y1) is the point and m is the slope
Example:
y – 1 = 2(x – 2)
General Form:
Example:
4x – 3y = 12
Two-Intercepts Form:
where a is the x-intercept and b is the y-intercept
Example:
y
xO 2 4 6
2
4
6
–6
–4
–2–6 –4 –2
y
xO 2 4 6
2
4
6
–6
–4
–2–6 –4 –2
y
xO 2 4 6
2
4
6
–6
–4
–2–6 –4 –2
y
xO 2 4 6
2
4
6
–6
–4
–2–6 –4 –2
3
21
23
yx
// Lines and Lines:
1st: Sketch y = ¾x + 1
2nd: Sketch the line parallel to it, and have y-intercept = –2.Q: What is the slope?
Q: What is the equation?
3rd: Sketch the line perpendicularto it and have y-intercept = 4.Q: What is the slope?
Q: What is the equation?
y
xO 2 4 6
2
4
6
–6
–4
–2–6 –4 –2