Finding intercepts of Linear Equations:
An x-intercept is the x-coordinate of a point where a graph crosses the x-axis. The x-intercept has a y value of zero.
A y-intercept is the y-coordinate of a point where a graph crosses the y-axis. The y-intercept has an x value of zero.
Example:
Find the x-intercept and y-intercept for the graph of the line.
Solution:
The x-intercept of this graph is 4. The coordinates of the point at the x-intercept is (4, 0).
The y-intercept of this graph is 2. The coordinates of the point at the y-intercept is (0, 2).
Finding the x-intercept:
Example:
Find the x-intercept of the graph of the equation 2x - 3y = 8.
Solution:
To find the x-intercept of 2x - 3y = 8, let y = 0.
2x - 3y = 8
2x - 3(0) = 8
2x = 8
x = 4 The x-intercept is 4. The line crosses the x-axis at the point (4, 0).
Finding the y-intercept:
Example:
Find the y-intercept of the graph of the equation 3x + 2y = -6.
Solution:
To find the y-intercept of 3x + 2y = -6, let x = 0.
3x + 2y = -6
3(0) + 2y = -6
2y = -6
y = -3 The y-intercept is -3. The line crosses the y-axis at the point (0, -3).
Assignment:
Find the x-intercept of the graph of each equation.
1. -x + 3y = -18
2. 2x - 2y = 10
3. -2x - y = 6
4. -3x + 4y = 12
5. 3x + 3y = -10
Find the y-intercept of the graph of each equation.
6. -2x -3y = 35
7. 3x + 5y = -10
8. 4x - 3y = 21
9. 0.5x + 0.4y = 16
10. -3x - 2y = 4
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