Problem 94 - Intermediate Algebra

Question

Solve each equation. $$ |75-x|=-1 $$

Step-by-Step Solution

Answer

The equation has no solution, as the absolute value cannot equal a negative number.

Step 1: Understanding Absolute Values

The absolute value function, denoted as \(|x|\), represents the distance of a number from zero on the number line. This distance is always non-negative. Hence, \(|75-x|=-1\) has no solution because the absolute value can never equal a negative number.

Step 2: Conclusion

Since the equation \(|75-x| = -1\) involves an absolute value on the left-hand side and a negative number on the right-hand side, there are no possible values for \(x\) that can satisfy this equation.

Key Concepts

Equation Solving

When we talk about solving equations, we're looking to find the value of the variable that makes the equation true. An equation is like a balance scale; whatever you do to one side, you must do to the other to keep it balanced. However, absolute value equations add a twist to this process.

Absolute value equations are equations where the variable is inside an absolute value symbol, like | x |. The key thing to understand here is that whatever is inside the absolute value symbol will always be taken as a positive number or zero. So, when solving these kinds of equations, the possible solutions are determined by the non-negative nature of the absolute value.

• Identify the absolute value expression in the equation.
• Determine if the equation has real solutions by evaluating if the expression equals a non-negative number.
• If the expression on the other side of the equation is negative, as in \(|75-x| = -1\), it's immediately clear there can be no solution.

By recognizing these properties, you can efficiently solve or dismiss absolute value equations.

Distance on Number Line

The concept of distance on the number line is closely tied to absolute values. Imagine you have a ruler laying flat, with zero at the center. Each mark to the left and right represents a number's distance from zero.

Since distance can never be negative, every distance measurement is at least zero. Absolute values work similarly. They measure how far a number is from zero, regardless of direction.

• Absolute value \(|x|\) answers the question: "How many units away from zero is \(|x|\)?"
• This is why \(|75-x|\) represents the distance between \(|75\) and \(|x\)\.)

Given the constraints of absolute values, if you see an equation with an absolute value set equal to a negative number, such as \(|75-x|=-1\), you immediately know there's an issue because a distance can't be negative.

Non-Negative Values

The concept of non-negative values is vital in understanding absolute value equations. A non-negative value is any number that is zero or greater. Absolute values, which capture a form of distance, can never be less than zero. This characteristic underpins why some equations, like \(|75-x| = -1\), have no solutions.

When facing absolute value equations:

• First, confirm the value that the absolute expression is set equal to. It should be non-negative.
• If the right side of the equation is negative, there are no real solutions, because a non-negative can't equal a negative.
• This property ensures the truth and consistency of our math and helps identify impossible scenarios quickly.

Understanding non-negative values ensures that you begin each problem with a good grasp of whether solving it is indeed feasible.