Which of the following expressions are polynomials in one variable and which are not? State reasons for your answer :
(i) `3x^2-4x+15`
(ii) `y^2+2sqrt(3)`
(iii)`3sqrt(x)+sqrt(2)x`
(iv) `x-4/x`
(v) `x^12 + y^3 + t^50`

Explanation

To determine whether the given expressions are polynomials in one variable or not, we need to analyze each expression based on the definition of a polynomial. A polynomial in one variable is an expression that consists of terms that are non-negative integer powers of a single variable.

Let's evaluate each expression step by step:

### Step 1: Analyze the first expression `3x^2 - 4x + 15`
- **Terms**: `3x^2`, `-4x`, `15`
- **Variable**: The only variable present is `x`.
- **Powers**: The powers of `x` are 2 (from `3x^2`), 1 (from `-4x`), and 0 (from `15` since any constant can be considered as `x^0`).
...