X and Y Intercepts
m = ________________
The point at which a line crosses the x or y axis is called an
intercept. When a line is graphed, every point on that line is
called a “solution” to that graph.
Identify the x- and y-intercept of each line. Then determine the
slope.
x-int: _________
y-int: _________
m = _________
x-int: _________
y-int: _________
m = _________
x-int: _________
y-int: _________
m = _________
x-int: ______
y-int: ______
m = ______
x-int: ________
y-int: ________
m = _________
Slope-Intercept Form
Determining whether an ordered pair is a solution to an
equation:
Now, graph the solutions that were TRUE for the equation
y = 2x + 5.
Find the slope:
The equation y = 2 x + 5 has variables x and y. All of the
ordered pairs in the form (x, y) that make this equation true are
called “solutions” of this equation. To check to see if an
ordered pair is a solution to an equation, substitute the values of
x and y into the equation and evaluate.
Example 1: Determine if the point (0, 5) is a solution to the
equation y = 2 x + 5 .
What is the y-intercept:
What do you notice about the slope and y-intercept and the
equation that was used to determine that these points were true?
Example 2: Determine if the point (-4, -3) is a solution to the
equation y = 2 x + 5 .
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Example 3: Determine if the point (0, 0) is a solution to the
equation y = 2 x + 5 .
The equation y = 2 x + 5 is written in a special form called
slope-intercept form.
y = mx + b
Guided Practice:
Guided Practice:
1.
Write the equation in slope-intercept form of a line with a
Slope = 2 and y-intercept = -4?
1.
Write the equation in slope-intercept form of a line with a
Slope = 2 and y-intercept = -4?
2.
Write the equation of each line below.
2.
Write the equation of each line below.
Slope: ____ y-int: ______
Slope: ____ y-int: ______
Slope: ____ y-int: ______
Slope: ____ y-int: ______
Equation: _____________
Equation: _____________
Equation: _____________
Equation: _____________
Slope: ____ y-int: ______
Slope: ____ y-int: ______
Slope: ____ y-int: ______
Slope: ____ y-int: ______
Equation: _____________
Equation: _____________
Equation: _____________
Equation: _____________