I was certainly delighted to learn of the hidden word "vary" nestled into the word variable. But discovering this actually made me more skeptical about the definition of variables, prompting me to ask, ⁉️"Does the value of all variables vary?"⁉️
Vary: not consistent, liable to change.
Let's consider 2 examples:
1) For x + 6 = 12, it's easy to tell that x = 6 because you know that 6 + 6 =12. Therefore, x has one value here. It does not vary because it cannot be any other number besides 6 for the equation to be true.
On the other hand...
2) For y = 4x + 7 is a linear equation where the values of x and y vary because they represent one of the infinite amount of coordinate points (x, y) on that particular line.
So even though we call letters in math variables, it doesn't mean that they all vary in value. Some are just one value.
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