When the slope is 0 What does that mean?
Now we see why a vertical line has an undefined slope. Because we can't divide by zero! Usually in math, when something is "undefined" it means that somewhere, something is being divided by 0. And that's a no-no. It has no meaning.
When the 0 is on the "top" of the fraction, that would mean that the two y-values are the same. Thus that line is horizontal (slope of 0). If the "bottom" of the fraction is 0 that means the two x-values are the same. Thus that line is vertical (undefined slope).
- Algebra 1 – How to Graph a Linear Equation Using Slope and y
- Step 1: Put the equation in Slope Intercept Form.
- Step 2: Graph the y-intercept point (the number in the b position) on the y-axis.
- Step 3: From the point plotted on the y-axis, use the slope to find your second point.
- Step 4: Draw your line using the two points you plotted (y-intercept (b) first, slope (m) second.
- The coordinates of every point on the line will solve the equation if you substitute them in the equation for x and y. The equation of any straight line, called a linear equation, can be written as: y = mx + b, where m is the slope of the line and b is the y-intercept.
- In geometry, a horizontal line is one which runs from left to right across the page. It comes from the word 'horizon', in the sense that horizontal lines are parallel to the horizon. The horizon is horizontal. Its cousin is the vertical line which runs up and down the page.
Since we did not have a change in the x values, the denominator of our slope became 0. This means that we have an undefined slope. If you were to graph the line, it would be a vertical line, as shown above. This form can be handy if you need to find the slope of a line given the equation.
- When you look at the two lines, you can see that the blue line is steeper than the red line. It makes sense the value of the slope of the blue line, 4, is greater than the value of the slope of the red line, . The greater the slope, the steeper the line. The next example shows a line with a negative slope.
- It is a vertical line through 2 on the - axis. Vertical Lines A vertical line is a line whose equation is of the form =ℎ, where ℎ is a real number. All points that lie on the line have an -coordinate of ℎ. The slope of any vertical line is undefined.
- To use the vertical line test, take a ruler or other straight edge and draw a line parallel to the y-axis for any chosen value of x. If the vertical line you drew intersects the graph more than once for any value of x then the graph is not the graph of a function.
Updated: 7th September 2018