Download 2011-2012 - Bleckley County Schools

Unit 6- Linear Functions
Vocabulary
Lesson 21 – Slope

The steepness of the line is called the slope. The slope shows
the rate at which tow quantities are changing. Specifically, it is
the ratio of the vertical change to the horizontal change, or
rise
.
run
Symbols and
Formulas
Slope:
rise y

run x
y  y2
 1
x1  x2
m
Slope-Intercept
Form:
y  mx  b
m is the slope
b is the y-intercept
Point-Slope Form:
y  y1  m( x  x1 )
m is the slope
(x1, y1) is point on line
Direct Proportion:
y  mx or
y
m
x
m is constant of
proportionality.
Similar triangles have the same shape, but not necessarily the
same size. The ratios of the lengths of their corresponding sides
are equal
Lesson 22 – Slopes and y-intercepts


The point at which the graph crosses the y-axis is called the yintercept. Any point (0,b) that is a solution of the equation is
the y-intercept.
The equation y = 2x+5 is written in a special form called the
slope-intercept form.

You can use the point-slope form to write the equation in slopeintercept form.
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Lesson 23 – Proportional Relationships


A proportion shows that two ratios are equal in value.
A unit rate is a rate that, when expressed as a fraction, has a 1
in the denominator. If a unit rate involves money, it is called a
unit price.
Lesson 24 – Direct Proportions

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A direct proportion is a special kind of linear equation. In a
direct proportion, the ratio of two variables, such as y an x, is a
constant, m. We can say that y is directly proportional to x.
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Lesson 25 – Work with Linear Functions

A linear function is a special kind of function whose graph is a
straight line (y=mx+b). A nonlinear function is any function
that is not linear.
 Dependent variable is often called the y-value and
the x-value is often called the independent variable.
 The initial value is the value of y when x equals 0. In a graph,
the rate of change is the same as the slope.
Lesson 26 – Compare Relationships in Different Ways
none