Question 384088: is x suppose to equal a number that should replace the x or is it all ways one
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! In a general expression, x represents any number.
To solve for a specific number, you replace x with that number in the equation.
example:
y = x^2 + 3*x - 5
If you want to know the value of y when x = 3, you replace x with 3 in the equation to get:
y = 3^2 + 3*3 - 5 = 9 + 9 - 5 = 18 - 5 = 13
When you get into functional notation (if not already), then you will see:
f(x) = x^2 + 3*x - 5
When x = 3, then you will see:
f(3) = 3^2 + 3*3 - 5
The 3 replaces the x to give you the value of the equation when x = 3.
If you want to know the value of y or f(x), when x = 5, then you replace x with 5, etc.
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