Slope and Graphing Lines

Finding Slope and Graphing Quiz Review

Finding Slope when given 2 points.

• Formula  $\frac{y-y}{x-x}$  

• Remember an ordered pair is written like (x,y)

• Subtract the y values for the numerator

• Subtract the x values for the denominator

Multiple Choice

Find the slope:

(-3, 3) and (7, 6)

• 3/4

• 3/10

• -4/3

• -10/3

Multiple Choice

Find the slope of the line that passes through

(10, 1) and (5, 2)

• -1/5

• 1/5

• 5

• -5

Finding Slope on a graph

• Start with the point furthest to the Left

• Count how many spaces you move up or down (up = positive & down = negative)  RISE

• Count how many spaces you move right or left (right = positive and left = negative)  RUN

• Slope is

   $\frac{Rise}{Run}$ 

Multiple Choice

Find the slope of the line in simplest form.

• -2

• -1

• 2

• 1

Multiple Choice

What is the slope of this line?

• -1

• 1

• 0

• Undefined

Multiple Choice

What is the slope of the line?

• 1

• -1

• 0

• Undefined

Graphing a line

• To graph a line, the equation needs to be in slope intercept form

• y = mx + b

• m = the slope

• b = the y-intercept (where the lines crosses the y-axis)

Example: y = 1/2x + 6

• The slope is where the "m" would be

• So here, the slope is 1/2

• The y-intercept is where the "b" would be

• So here, the y-intercept is 6

Multiple Choice

Which of these represents slope-intercept form?

• y - y₁ = m(x-x₁)

• Ax + By = C

• y = mx + b

Multiple Choice

What does "m" represent in y=mx+b?

• y-intercept

• slope

• Linear

• Horizontal

Multiple Choice

Determine the slope and y-intercept. y = 3/2x + 3

• slope: 5 y-intercept: (0,3)

• slope: 3/2 y-intercept: (0,3)

• slope: 4 y-intercept: (0,3/2)

• slope: 1/5 y-intercept: (0,5)

Multiple Choice

What is the y-intercept in the following equation: y=-4x-5

• -4

• -4x

• 5

• -5

Multiple Choice

What is the y intercept? Make sure to write it as an ordered pair.

• (1,0)

• -1

• (0-1)

• (0,-2)

To graph a line:

• Look for the y-intercept (the "b" in the equation)

• Plot that point on the y-axis

• Look at the slope (the "m" in the equation)

• Move that many units up and over from your first point.

• Remember: Positive slope goes up and over. Negative slope goes down and over.

Finding an equation from a graph

• First look on the y-axis for the point. This will be the "b" in the equation.

• Then see if it is a positive or negative line.

• Count the Rise and the Run between two points. 

• Find the equation that has the same slope in the "m" spot.

Multiple Choice

Write the equation of the line.

• y = -2/3x + 4

• y = 2/3x + 4

• y = 3/2x + 4

• y = -3/2x + 4

Multiple Choice

Write the equation for the line.

• y= -1x+3

• y= 4x+3

• y=(1/4)x+3

• y= -4x+3

Multiple Choice

Write the equation of the line.

• y=(3/5)x-1

• y=(-3/5)x-1

• y=(5/3)x+1

• y=(3/5)x+1