Chapter 5: Problem 64
Determine the number of solutions to the system of equations. $$ \begin{aligned} x^{2}-y^{2} &=0 \\ |x| &=|y| \end{aligned} $$
Short Answer
Expert verified
There are infinitely many solutions.
Step by step solution
01
Understand the system of equations
The given system has two equations: 1. The first equation is a difference of squares: \[ x^2 - y^2 = 0 \] 2. The second equation involves absolute values: \[ |x| = |y| \]
02
Factorize the first equation
Rewrite the first equation using the difference of squares formula: \[ x^2 - y^2 = (x + y)(x - y) = 0 \] This equation is satisfied when either \( x + y = 0 \) or \( x - y = 0 \).
03
Solve each factor separately
1. For \( x + y = 0 \), solve for one variable in terms of the other: \[ x = -y \]2. For \( x - y = 0 \), solve for one variable in terms of the other: \[ x = y \]
04
Consider the absolute value condition
From the second equation \( |x| = |y| \), there are two scenarios to consider for each case:1. If \( x = |y| \), then \( x = y \) or \( x = -y \).2. These conditions must match the solutions obtained from the first equation.
05
Compile valid solutions
- From \( x = y \) and considering the absolute value condition, possible solutions are \((x, y) = (a, a)\) for any real number 'a'.- From \( x = -y \) and considering the absolute value condition, possible solutions are \((x, y) = (a, -a)\) for any real number 'a'.
06
Count the number of solutions
Since there are no further restrictions, there are infinitely many solutions for each case (both \( x = y \) and \( x = -y \)), leading to infinitely many solutions in total.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Difference of Squares
The concept of the 'difference of squares' is a fundamental algebraic technique. It’s important because it helps us simplify quadratic expressions and solve equations. The difference of squares refers to expressions of the form \[ a^2 - b^2 \]. The neat trick here is that it can be factored into a product of two binomials: \[ a^2 - b^2 = (a + b)(a - b) \]. This form is easier to work with, especially for solving equations.
Let's look at the example from the exercise:
Let's look at the example from the exercise:
- The first equation we have is \[ x^2 - y^2 = 0 \].
- Applying the difference of squares formula, we rewrite it as \[ (x + y)(x - y) = 0 \].
- This tells us that either \[ x + y = 0 \] or \[ x - y = 0 \] or both.
Absolute Value Equations
Another important aspect of our exercise is 'absolute value equations'. The absolute value \(|x|\) of a number is its distance from zero on the number line, regardless of direction. So, \(|x| = a\) means \(x\) is either \(a\) or \(-a\).
Consider the second equation in the problem:
Consider the second equation in the problem:
- \(|x| = |y|\) tells us that the absolute values of \(x\) and \(y\) are the same.
- This implies two cases: \(x = y\) or \(x = -y\).
Solutions to Equations
Finally, let's discuss 'solutions to equations'. Solving equations is about finding all values that make the equation true. In this exercise:
- We derived \(x = y\) and \(x = -y\) from our factored form and absolute value conditions.
- We then matched these with the solutions from the difference of squares.
- Upon analysis, it’s clear that both \(x = y\) and \(x = -y\) offer infinitely many solutions.