Writing Equations of Lines from Two Points

What is the first step in writing the equation of a line given two points?

• Use the slope formula

• Plot the points on a graph

• Find the y-intercept

• Convert to slope-intercept form

What is the slope formula?

• y2 + y1 over x2 + x1

• x1 minus x2 over y1 minus y2

• y2 minus y1 over x2 minus x1

• x2 minus x1 over y2 minus y1

In the first example, what is the slope of the line passing through the points (5, 4) and (3, 2)?

• -1

• 1

• 0

• 2

What is the equation of the line in slope-intercept form for the first example?

• y = 2x + 1

• y = x - 1

• y = x + 1

• y = 2x - 1

In the second example, what is the slope of the line passing through the points (-2, -5) and (2, 3)?

• 2

• 1/2

• 3/4

• 1

What is the equation of the line in slope-intercept form for the second example?

• y = 2x - 1

• y = 2x + 1

• y = x + 1

• y = x - 1

In the third example, what is the slope of the line passing through the points (7, 5) and (10, 6)?

• 2

• 1/2

• 1

• 3/4

What is the equation of the line in slope-intercept form for the third example?

• y = 2x - 1

• y = 1/2x - 2

• y = 2x + 1

• y = 1/2x + 2

What is the slope of the line passing through the points (2, -1) and (-8, 4)?

• -3/4

• 3/4

• -1/2

• 1/2

What is the final equation of the line in slope-intercept form for the third example?

• y = -3/4x - 6

• y = -3/4x + 6

• y = -3/4x - 4

• y = -3/4x + 4