Transcript Glencoe Pre

Over Lesson 5–3
Write an inequality for the sentence.
A number decreased by 7 is at most 9.
Write an inequality for the sentence.
There are more than 500 students (s) at
Candlewood Middle School.
What inequality
represents the
graph?
A.
B.
C.
D.
A
B
C
D
You have already used the Properties of
Equality to solve equations.
(Lessons 4–3 and 4–4)
• Solve inequalities with Addition and
Subtraction.
• Solve inequalities with Multiplication and
Division (tomorrow).
So you want to solve inequalities?
Maybe you’re crazy!…lol
• To solve inequalities, first pretend they are equal.
This will allow you to use your previously learned
algebra skills.
• After you have completed the problem as if it were
equal, we graph the critical point (what it is “equal
to”) and make sure we make either an open circle or
closed circle (depending on the inequality)
• Test values using the original inequality and write
the inequality the graph represents.
Solve an Inequality
Solve y + 5 > 11.
y + 5 > 11
Write the inequality.
y + 5 = 11
Pretend it is equal
-5
y
-5
= 6
Subtract 5 from both sides.
This is our critical point (graph it)
0
6
Test values to the left and right of 6. Plug in 0 into the
original inequality. Does it work? Try 7 into the original
inequality. Does it work? Now shade!
Answer: The solution is y > 6.
Solve an Inequality
Solve y - 3 ≤ -2.
y - 3 ≤ -2
Write the inequality.
y - 3 = -2
Pretend it is equal
+3
y
+3
= 1
Add 3 to both sides.
This is our critical point (graph it)
0
1
Test values to the left and right of 1. Plug in 0 into the
original inequality. Does it work? Try 3 into the original
inequality. Does it work? Now shade!
Answer: The solution is y ≤ 1.
Solve an Inequality
Solve y - 5 > -9.
y - 5 > -9
Write the inequality.
y - 5 = -9
Pretend it is equal
+5
y
+5
= -4
Add 5 from both sides.
This is our critical point (graph it)
-4
0
Test values to the left and right of -4. Plug in -5 into the
original inequality. Does it work? Try 0 into the original
inequality. Does it work? Now shade!
Answer: The solution is y > -4.
Solve an Inequality
Solve y + 6 ≥ 6.
y+6≥6
Write the inequality.
y+6=6
Pretend it is equal
-6 -6
y
=0
Subtract 6 from both sides.
This is our critical point (graph it)
0
Test values to the left and right of 0. Plug in -1 into the
original inequality. Does it work? Try 2 into the original
inequality. Does it work? Now shade!
Answer: The solution is y ≥ 0.
Solve x + 9 < 13.
A. x < 22
B. x < 4
C. x < –4
D. x > 4
A.
B.
C.
D.
A
B
C
D
Solve
Graph the solution on a number line.
A.
;
B.
;
C.
D.
;
;
A.
B.
C.
D.
A
B
C
D
Let’s do some
practice at our seats
with this worksheet I
am about to handout!