4.2 Graphing Linear Functions Use tables and equations to graph linear functions.
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Transcript of 4.2 Graphing Linear Functions Use tables and equations to graph linear functions.
4.2 Graphing Linear FunctionsUse tables and equations to graph linear functions.
Parent FunctionsA family of functions is a group of
functions with common characteristics.
Simplest function with these characteristics is called a parent function.
The linear parent function is y = x or f(x) = x
Linear EquationModels a linear functionVariable cannot be raised to a
power other than 1y = 2x is linear but y = x2 and y =
2x are not.The y-intercept is the y-coordinate
of a point where the graph crosses the y-axis.
Slope-Intercept FormFor linear equations that are not
vertical.Remember, the slope of a vertical
line is undefined.
Ex: identify the slope and y-intercept for the linear equation y = 5x – 2
Slope: 5y-intercept: -2
Writing an EquationWhat is the equation of the line
with a slope of and y-intercept 7?Plug into slope-intercept form:
◦m = and b = 7◦y = -
From a GraphCrosses the y-axis at -2 so b = -2Pick two points to find the slope:
(0, -2) and (1, 0)m = 2Write an equation using slope-
intercept form:◦y = 2x – 2
From Two PointsFind the equation of the line that
passes through (2,1) and (5, -8)Use the points to find slope
◦m = -3Use slope and one of the points to find
by = -3x + b and plug in the point (2, 1)1 = -3(2) + b1= -6 + b7 = bWrite the equation
◦y = -3x + 7
GraphingWhat is the graph of y = 2x – 1?
PracticeWhat is the graph of each linear
equation?
y = -3x + 4
y = 4x – 8