Questions: Why are the equations (x+y-y=x) and (x-y+y=x) called identities?
These equations are called identities because the variables can be replaced with any number, and after completing the operations, the result is the original number.
I can test this by replacing the variables with numbers. If I replace (x) with 10 and (y) with 4, the resulting number sentence (10+4-4=10) is true. The other resulting number sentence (10-4+4=10) is also true.
Transcript text: 2. Why are the equations $x+y-y=x$ and $x-y+y=x$ called identities?
These equations are called identities because the variables can be replaced with any number, and after completing the operations, the result is the original number.
I can test this by replacing the variables with numbers. If I replace $x$ with 10 and $y$ with 4 , the resulting number sentence $10+4-4=10$ is true. The other resulting number sentence $10-4+4=10$ is also true.
Solution
Solution Steps
Step 1: Understanding the Equations
The equations given are \(x + y - y = x\) and \(x - y + y = x\). These are called identities because they hold true for any values of \(x\) and \(y\).
Step 2: Simplifying the First Equation
For the equation \(x + y - y = x\), simplify by canceling out \(y\) and \(-y\):
\[ x + y - y = x \]
\[ x = x \]
Step 3: Simplifying the Second Equation
For the equation \(x - y + y = x\), simplify by canceling out \(-y\) and \(y\):
\[ x - y + y = x \]
\[ x = x \]
Final Answer
The equations are called identities because they hold true for any values of \(x\) and \(y\).