Slope-Intercept Form

**Slope-Intercept Form**

When graphing a line, it is often helpful to write the equation in slope-intercept form, **y = mx + b**, where **m** is the slope of the line, and **b** is the y-intercept.

The slope of a line may also be determined when two points on the line are known. The slope is calculated as the change in the *y* values over the change in the *x* values.

Linear inequalities may be graphed in the same way as lines. Graph the equation as if it had an equal sign. Use a dashed line for < or >. Use a solid line for __<__ or __>__. Test a point not on the line to check whether it is a solution of the inequality. If the test point is a solution, shade its region. If the test point is not a solution, shade the other region.

**Practice**

1. Find the x and y-intercepts, slope and graph of 6x + 5y = 30.

2. Find the x and y-intercepts, slope and graph of x = 3.

3. Find the x and y-intercepts, slope and graph of y = -4.

4. Write in slope-intercept form the line that passes through the points (4, 6) and (-4, 2).

5. Write in slope-intercept form the line perpendicular to the graph of 4x - y = -1 and containing the point (2, 3).

6. Graph the solution set of x - y __>__ 2.

7. Graph the solution set of -x + 3y < - 6.

**Answer Key**

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