This is an introduction to drawing lines when given the slope and the y-intercept in an equation form. Remember that the y-intercept is where the graph crosses the y-axis; this is where we usually start. First, find the y-intercept, then determine the slope. For now, just focus on whether the slope is positive or negative.
Here are the variables we will start using in our function:
- \( m = slope \)
- \( b = y-intercept \)
The equation is y = mx + b. The x and y variables remain as letters, but m and b are replaced by numbers (ex: \( y = 2x + 4 \), \( slope = 2 \) and \( y-intercept = 4 \) ). The following video will show a few examples of understanding how to use the slope and intercept from an equation.
Video Source (03:53 mins) | Transcript
\( y = mx + b \)
This equation is called the slope-intercept form because the two numbers in the equation are the slope and the intercept. Remember, the slope (m) is the number being multiplied to x and the intercept (b) is the number being added or subtracted.
- Khan Academy: Intro to Slope-Intercept Form (08:59 mins; Transcript)
- Khan Academy: Worked Examples: Slope-Intercept Intro (04:39 mins; Transcript)
Practice Problems1. Find the slope of the line:
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