2-3 Linear Functions and Slope-Intercept FormI can write and graph linear equations by using slope-intercept form.

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

SlopeRatio of the vertical change to

the horizontal change

The slope formula is

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 (0,7)?

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

AssignmentOddsP.78 #13-19, 25-33, and 58