y = mx +
b
stope
The slope goes down 2 and right 3: rise
-2
run
y =
2
3
x +4
The y-intercept is 4.
1 0
2
Linear inequalities in two variables, such as y > 2x - 4, are graphed by first drawing either a dashed line (for < or >) or a solid line (for ≤ or 2).
Then the region above or below that line is shaded to show which points satisfy the inequality.
Chapter 1 also introduced transformations. In Chapter 2, you will further investigate transformations of linear functions and summarize the transformations algebraically.
Real-world data sometimes show a linear relationship. If you calculate a line of best fit, then you can use it to make predictions about the data. In general, the study of relationships between variables is called regression.
The absolute value of a number x, written |x|, represents its distance from zero on a number line. The value of x could be positive, negative, or zero, but its absolute value is always nonnegative. To solve an absolute value equation or inequality, you must consider each possibility.
x= 4
X≥4
The distance from zero is 4.
The distance is greater than or equal to 4.
....
654-3-2-10
1 2 3 4 5 6
x=-4ORx=4
x≤-4 OR x≥4
x≤ 4
The distance is less than or equal to 4.
2 3 4
x≥-4 AND x ≤ 4
Because an absolute value is never negative, the graph of the absolute-value function
f(x) = [x) has two linear pieces that form a
V shape with a vertex at (0, O). As shown at right, a variety of absolute-value functions
can be created by transforming f(x) = |x|.
(x) = 1x
g(x) = |x + 31
The graph of
g (x) = |x+31-5
is a translation of
f (x) = |x| left 3 and
down 5
© Houghton Milfin Harcourt Publishing Company
58
Holt McDougal Algebra
4