# If t^2 = x can't I just replace t^2 with x?

1. Apr 24, 2015

### Tyrion101

Rather than having to take the root of t? It doesn't seem like there's a rule against it, unless it is for a specific problem.

2. Apr 24, 2015

### Fredrik

Staff Emeritus
The statement $t^2=x$ is saying that the expressions (strings of text) $t^2$ and $x$ represent the same number. So yes, you can certainly replace one with the other. For example if you're asked what $t^6$ is, you can write $t^6=(t^2)^3=x^3$.

But I'm not sure what exactly you have in mind. Perhaps you can clarify. Is there a specific problem where someone has told you that you can't replace $t^2$ with $x$?

Note by the way that if you take the square root of both sides, you get $|t|=\sqrt{x}$, not $t=\sqrt{x}$. The statement $t^2=x$ implies that either $t=\sqrt{x}$ or $t=-\sqrt{x}$.

3. Apr 24, 2015

### Tyrion101

No no specific problem, I was just trying to make my life a bit easier.