Lesson Example Discussion Quiz: Class Homework |
Step-3 |
Title: Linear inequalities in one or two variables |
Grade: 1400-a Lesson: S1-L4 |
Explanation: Hello Students, time to practice and review the steps for the problem. |
Lesson Steps
Step | Type | Explanation | Answer |
---|---|---|---|
1 |
Problem |
Solve the inequality \$ | 3x - 2 | + | 2x + 1 | < 5 \$. |
|
2 |
Tip |
When \$3x - 2 ge 0\$ and \$ 2x + 1 ge 0 \$ (both absolute values are positive). |
|
3 |
Step |
In this case, the inequality takes a positive value and then simplifies the inequality |
(3x - 2) + (2x + 1) < 5 5x - 1 < 5 \$5x - \cancel1 + \cancel1 < 5 + 1\$ |
4 |
Step |
After simplification |
\$ 5x < 6 \$ \$ x < 6/5 \$ |
5 |
Tip |
When \$3x - 2 < 0 and 2x + 1 ge 0\$ (the first absolute value is negative, the second is positive). |
|
6 |
Step |
In this case, the inequality takes a positive and negative value and then simplifies the inequality |
-(3x - 2) + (2x + 1) < 5 -3x + 2 + 2x + 1 < 5 -x + 3 < 5 |
7 |
Step |
Subtracting 3 from both sides, then we get |
\$- x + \cancel3 - \cancel3 < 5 - 3\$ -x < 2 |
8 |
Step |
Multiplying both sides by - 1 (remember to reverse the inequality when multiplying or dividing by a negative number), we have |
x > - 2 |
9 |
Tip |
When 3x - 2 < 0 and 2x + 1 < 0 (both absolute values are negative) |
|
10 |
Step |
In this case, the inequality takes a negative value and then simplifies the inequality |
-(3x - 2) + (-(2x + 1)) < 5 -3x + 2 - 2x - 1 < 5 -5x + 1 < 5 |
11 |
Step |
Subtracting 1 from both sides, then simplify |
\$ - 5x + \cancel1 - \cancel1 < 5 - 1 \$ \$ - 5x < 4 \$ \$ x < 4/(-5) \$ |
12 |
Step |
Therefore, the solution to the inequality \$ | 3x - 2 | + | 2x + 1 | < 5 \$ is \$ x < 6/5 \$, \$ x > - 2\$ and \$ x < - 4/5 \$. |
|
13 |
Choice.A |
Option A is incorrect because it incorrectly states that x > 2, which is not part of the solution set |
\$ x < 6/5 \$, \$ x > 2\$ and \$ x < 4/5 \$ |
14 |
Choice.B |
Option B is wrong as it claims \$x > 6/5\$ and \$x < −4/5\$, contradicting the obtained solutions |
\$ x > 6/5 \$, \$ x > - 2\$ and \$ x < - 4/5 \$ |
15 |
Choice.C |
Wrong due to including x > 2, which isn’t a valid solution in analyzed cases |
\$ x < 6/5 \$, \$ x > 2\$ and \$ x < - 4/5 \$ |
16 |
Choice.D |
Option D is correct because it correctly identifies the ranges for x based on these conditions |
\$ x < 6/5 \$, \$ x > - 2\$ and \$ x < - 4/5 \$ |
17 |
Answer |
Option |
D |
18 |
Sumup |
Can you summarize what you’ve understood in the above steps? |
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