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WRITE LINEAR
EQUATIONS IN
SLOPEINTERCEPT
FORM
December 2, 2013
Pages 283-285
Copy and complete the statement.
1.
In the equation y = mx + b, the value of m is the ?
of the graph of the equation.
ANSWER
2.
In the equation y = mx + b, the value of b is the
of the graph of the equation.
ANSWER
3.
slope
y-intercept
Two lines are ? if their slopes are equal.
ANSWER
parallel
?
Find the slope of the line that passes through the points.
4.
(4, 5), (2, 3)
ANSWER
1
5.
(0, – 6), (8, 0)
ANSWER
3
4
6.
(0, 0), (– 1, 2)
ANSWER
–2
Identify the slope and the y-intercept of the line with
the equation.
7.
y=x+1
ANSWER
8.
y= 3x–6
4
ANSWER
3 , –6
4
ANSWER
– 2 ,– 2
5
9. y = – 2 x– 2
5
1, 1
Evaluate the function when x = – 2, 0, and 4.
10.
f(x) = x – 10
ANSWER
– 12, – 10, – 6
11.
f(x) = 2x + 4
ANSWER
0, 4, 12
12.
f(x) = – 5x – 7
ANSWER
3, – 7, – 27
13. Write an equation of the line with a slope of – 2
and a y -intercept of 5.
y = mx + b
Write slope-intercept form.
y = – 2x + 5
Substitute – 2 for m and = for b.
14. Which equation represents the line shown?
2
B y = – 5x + 3
y=– x+3
A
5
2
C
y=–
2
x+1
5
D
2
y = 3x + 5
The slope of the line is rise = –2 = – 2 .
run
5
5
The line crosses the y-axis at (0, 3). So, the
y-intercept is 3.
Write slope-intercept form.
y = mx + b
y=– 2 x+3
5
Substitute –2 for m and 3 for b.
5
15. Write an equation of the line shown in
slope-intercept form.
SOLUTION
STEP 1 Calculate the slope.
STEP 2
y 2 – y1
– 1 – (– 5)
4
m = x –x =
=
3–0
2
1
3
Write an equation of the line. The line
crosses the y-axis at (0, – 5). So, the
y-intercept is – 5.
Write slope-intercept form.
y = mx + b
y= 4 x–5
3
Substitute 4 for m and – 5 for b.
3
16. Write an equation for the linear function f with
the values f(0) = 5 and f(4) = 17.
SOLUTION
STEP 1
Write f(0) = 5 as (0, 5) and f (4) = 17 as (4, 17).
STEP 2
Calculate the slope of the line that
passes through (0, 5) and (4, 17).
y2 – y1
m=
x2 – x1 =
17 – 5
4–0
12
= 4 =3
STEP 3
Write an equation of the line. The
line crosses the y-axis at (0, 5). So,
the y-intercept is 5.
Write slope-intercept form.
y = mx + b
y = 3x + 5
ANSWER
The function is f(x) = 3x + 5.
Substitute 3 for m and 5 for b.
HOMEWORK
Chapter 5, section 1
Pages 286-289
#4-14, even
#18-38, even
#53-54, all