Slope Review

Slope Review

Review of slope from equations, zero slope, undefined slope, and parallel/perpendicular slopes.

Slope from slope-intercept form

If the equation is in slope-intercept form (solved for y), then the slope is the number IN FRONT OF the x. NOT the x.

Example: y = mx + b, m is the slope. NOT mx.

mx + b = y, m is still the slope.

Multiple Choice

What is the slope in the equation y = 7x - 4

• 7

• 7x

• -4

• 1

Multiple Select

Choose all of the equations in which the slope is -5.

• y = -5x + 2

• y = 2x - 5

• 7 - 5x = y

• -5x + y = 7

Slope from any equation

To find the slope from any equation, solve for y first to put the equation into slope-intercept form. THEN look at the slope.

Multiple Choice

What is the slope of the equation 3x - 4y = 8?

• 3/4

• 4/3

• -3/4

• -4/3

Multiple Select

Choose all of the equations in which the slope is -2/3.

• 
  

  $y=-\frac{2}{3}x\ -\ 8$

• $2x\ -\ 3y\ =\ 15$

• $-2x\ +\ 3y\ =\ 15$

• $6x\ +\ 9y\ =\ -21$

Zero Slope

Since the slope is the number in front of x, the equation for ZERO slope looks like this: y=0x+b.

However, since any number (in this case, "x") times 0 equals 0, the equation ends up looking like this: y=b, where b is the y-intercept.

Multiple Select

Which graphs show zero slope?

Multiple Choice

What is the equation for the line shown in the graph?

• y = 4

• x = 4

• y = -4

• x = -4

Undefined Slope

A line with an undefined slope creates a vertical line. All the x-values of a vertical line are equivalent. Therefore the equation of a vertical line is x = a.

Multiple Select

Choose all the graphs that show an undefined slope.

Fill in the Blanks

Parallel Slopes

In order for two lines to be parallel, the slopes of their equations must be the same.

Multiple Select

Select the two equations that would create parallel lines.

• $y=\frac{2}{3}x-9$

• $y=-\frac{3}{2}x\ +\ 6$

• $y=-\frac{2}{3}x-5$

• $y=\frac{3}{2}x+9$

• $y=\frac{2}{3}x-4$

Perpendicular Slope

In order for two lines to be perpendicular, the slopes of their equations must be opposite reciprocals of one another.

_{Perpendicular lines can also be made if one line has a zero slope and the other has an undefined slope.}

Multiple Select

Select the two equations that would create perpendicular lines.

• $y=5x+7$

• $y=-5x-9$

• $y=-\frac{1}{5}x+3$

• $y=0.5x+2$

• $x=\frac{1}{5}y$

Multiple Choice

Which equation represents the line that would be perpendicular to y = 5, and would pass through the point (-7,2)?

•  $y=5$  

•  $x=-7$  

•  $y=-7$  

•  $x=2$  

•  $y=2$