Find the roots of the following quadratic equations, if they exist, by the method of completing the square:
(i) `2x^2-7x+3=0`
(ii) `2x^2+x-4=0`
(iii) `4x^2+4sqrt(3)x+3=0`
(iv) `2x^2+x+4=0`

Explanation

Let's solve the given quadratic equations step by step using the method of completing the square.

### (i) Solve `2x^2 - 7x + 3 = 0`

1. **Divide by 2**:
\[ x^2 - \frac{7}{2}x + \frac{3}{2} = 0 \]
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