2-5 The y-intercept of the Line
Key concept:
Part one: Where is the y-intercept.
The y-intercept of a line is the value of y at the point where the line crosses the y axis.
y= x+b (b is the y intercept)
What do you think x must be when finding the y intercept?!
Example:
What is the y-intercept of the graph of the equation y= x +3?
Your Turn:
What is the y-intercept of the graph of the equation y= x + 6?
Part two: Finding the y-intercept
Example:
For each graph or the graph of each equation find the y-intercept.
Your turn:
1) What is the y-intercept of the graph of the
equation y= -5x-1?
2) Your friend says that the graph of every
linear equation must cross the y-axis. Prove a
counter example to your friend’s statement.
Part three: What does the y-intercept represent?
Example:
The line models the total amount of snow on the
ground during a snowstorm.
What is the y-intercept of the line? What does
the y-intercept represent?
What is the slope of the line? What does the
slope represent?
Your turn:
A bottle of dish soap starts to leak. The line models the amount of dish soap
in the bottle.
What is the y-intercept of the line?
What does the y-intercept mean?