Chapter 1: Problem 54
Does the equation have a solution? Ex plain how you know without solving it. $$ \frac{x+3}{2 x+5}=1 $$
Short Answer
Expert verified
Answer: Yes, the equation does have a solution, because any value of x other than -5/2 results in a valid and defined equation.
Step by step solution
01
Consider the denominator
The equation will not have a solution if the denominator (2x + 5) results in zero because division by zero is undefined. So, we first need to figure out if there is any value of x that makes the denominator zero.
$$
2x + 5 = 0
$$
Solve for x:
$$
2x = -5 \\
x = -\frac{5}{2}
$$
02
Analyze the equation with the critical value
Since we found that there is one value of x (-5/2) which makes the denominator equal to zero, let's see if this value results in an undefined equation or if it is actually a solution.
Plugging in x=-5/2 into the equation:
$$
\frac{-\frac{5}{2}+3}{2\cdot\left(-\frac{5}{2}\right)+5} = 1
$$
03
Conclusion
Given x = -5/2, the denominator becomes zero:
$$
2\cdot\left(-\frac{5}{2}\right) + 5 = 0
$$
So, the equation is undefined for x = -5/2. However, this does not mean that there is no solution to the equation. The answer to the question "Does the equation have a solution?" is a definitive yes because any value of x other than -5/2 would make the equation defined and could potentially result in a true statement.
In other words, with any value of x other than -5/2, we have a valid equation. This means there could indeed be a value of x that makes the equation true, but we are not required to find one for this exercise. Thus, we can conclude that the equation does have a solution without actually solving for the value of x.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Understanding Denominators in Equations
When dealing with equations like \(\frac{x+3}{2x+5}=1\), it's important to consider the denominator, which is the expression below the fraction line. In this case, the denominator is \(2x + 5\). Denominators play a crucial role in determining whether the fraction, and in turn, the equation, is defined or undefined.
- If the denominator equals zero for a certain value of \(x\), the fraction becomes undefined, since division by zero is mathematically undefined.
- To identify these critical values, set the denominator equal to zero and solve for \(x\). For our equation, this looks like: \(2x + 5 = 0\), leading to \(x = -\frac{5}{2}\).
Recognizing Undefined Expressions
Undefined expressions occur in equations when a mathematical operation cannot be performed, usually because of division by zero. In the equation \(\frac{x+3}{2x+5}=1\), if \(2x + 5\) equals zero, the expression becomes undefined. Why does this matter?
- If we substitute \(x = -\frac{5}{2}\) into the equation, the denominator \(2\left(-\frac{5}{2}\right) + 5\) simplifies to zero.
- This zero denominator indicates that for \(x = -\frac{5}{2}\), the fraction no longer holds meaning in a mathematical context.
Solving Algebraic Equations
In algebra, finding solutions to equations involves determining which values of the variable make the equation true. For our equation \(\frac{x+3}{2x+5}=1\), we establish that \(x = -\frac{5}{2}\) cannot be a solution because it makes the equation undefined. Although the problem does not ask us to find the solution explicitly, knowing how to proceed is helpful.
- Start by rewriting the equation to eliminate the fraction: multiply both sides by the denominator \(2x + 5\).
- This results in: \(x + 3 = 2x + 5\).
- Next, solve for \(x\) by simplifying and rearranging terms: \(x + 3 = 2x + 5\Rightarrow 3 = x + 5\Rightarrow x = -2\).