Chapter 7: Problem 16
Solve each inequality and graph the solution on a number line. a. \(-2<6 x+8\) (a) b. \(3(2-x)+4 \geq 13\) (a) c. \(-0.5 \geq-1.5 x+2(x-4)\)
Short Answer
Expert verified
a) \(x > -\frac{5}{3}\); b) \(x \leq -1\); c) \(x \leq 15\).
Step by step solution
01
Simplify and Isolate for a
Start with the inequality \(-2<6x+8\). Subtract 8 from both sides to get \(-10<6x\). Then, divide every term by 6 to isolate \(x\). This results in \(x > -\frac{5}{3}\).
02
Graph Solution for a
Draw a number line and mark \(-\frac{5}{3}\). Since the inequality is \(x > -\frac{5}{3}\), use an open circle to indicate that \(-\frac{5}{3}\) is not included, and shade the line to the right to represent all numbers greater than \(-\frac{5}{3}\).
03
Distribute and Isolate for b
Start with the inequality \(3(2-x)+4 \geq 13\). Distribute the 3 to get \(6-3x+4 \geq 13\), which simplifies to \(10-3x \geq 13\). Subtract 10 from both sides to get \(-3x \geq 3\). Divide by -3, and remember to reverse the inequality sign to get \(x \leq -1\).
04
Graph Solution for b
On a number line, mark \(-1\) with a closed circle since the inequality includes \(-1\). Shade the line to the left to indicate all numbers less than or equal to \(-1\).
05
Simplify and Isolate for c
Start with the inequality \(-0.5 \geq -1.5x + 2(x-4)\). First, distribute 2 to get \(-0.5 \geq -1.5x + 2x - 8\). Combine like terms to simplify it to \(-0.5 \geq 0.5x - 8\). Add 8 to both sides to yield \(7.5 \geq 0.5x\). Divide each side by 0.5 to obtain the solution \(x \leq 15\).
06
Graph Solution for c
On a number line, mark 15 with a closed circle since \(x\) includes 15. Shade the line to the left to represent all numbers less than or equal to 15.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Graphing Solutions
When solving inequalities, graphing the solution gives us a visual representation of all possible solutions on the number line. It's an essential part of understanding inequalities as it helps to interpret the solution set.
To graph solutions:
To graph solutions:
- Identify the critical point—this is the number where the inequality changes.
- Determine whether to use an open or closed circle:
- Use an open circle for "less than" (<) or "greater than" (>) which means the point is not included in the solution.
- Use a closed circle for "less than or equal to" (≤) or "greater than or equal to" (≥) which means the point is included.
- Shade the portion of the number line that represents all the numbers that satisfy the inequality:
- Shade right for "greater than" (>) or "greater than or equal to" (≥).
- Shade left for "less than" (<) or "less than or equal to" (≤).
Number Line
A number line is a visual representation of numbers laid out on a straight path where equal intervals indicate the value of integers and other real numbers. It's a fundamental concept in mathematics and is extremely useful when working with inequalities.
Here's how to use a number line effectively with inequalities:
Here's how to use a number line effectively with inequalities:
- Position values on the line depending on whether they're positive or negative.
- Mark 'important' numbers from your inequality solution clearly, typically with circles.
- Use direction (left or right) to demonstrate the range of solutions.
Distributive Property
The distributive property is a powerful algebraic tool used to simplify expressions and make equations easier to solve. It allows you to multiply a single term by each term within a parenthesis.
For example, in the expression:
\[a(b + c) = ab + ac\]
This property makes complex algebraic operations more manageable by breaking them down into simpler components. Often encountered in solving inequalities, like in the example:
For example, in the expression:
\[a(b + c) = ab + ac\]
This property makes complex algebraic operations more manageable by breaking them down into simpler components. Often encountered in solving inequalities, like in the example:
- Multiply the term outside by every term inside the parenthesis:
- e.g., \(3(2-x)\) becomes \(6 - 3x\).
- Combine like terms if applicable to further simplify the equation.