Inputs and outputs of composite function

[Mark44]

U plug in x into the equation to find out what numbers y is greater than or equal to and same for the 3

"Textspeak" isn't allowed here. Please don't write "u" for "you".

 

[Coco12]

Okay, that makes sense now. You plug the x values into the equation, not the range.

So you plug in x values into equation to get the range? Does this always work. Because I know in some cases the domain is all real numbers but the range might not be.

 

[haruspex]

So you plug in x values into equation to get the range? Does this always work. Because I know in some cases the domain is all real numbers but the range might not be.

Why would that invalidate it? If the number you plug in is part of the domain then the number you get out must be part of the range.