Check whether the following are quadratic equations: (i) \((x+1)^2 = 2(x-3)\) (ii) \(x^2 - 2x = (-2)(3-x)\) (iii) \((x-2)(x+1) = (x-1)(x+3)\) (iv) \((x-3)(2x+1) = x(x+5)\) (v) \((2x-1)(x-3) = (x+5)(x-1)\) (vi) \(x^2 + 3x + 1 = (x-2)^2\) (vii) \((x+2)^2 = 2x(x^2-1)\) (viii) \(x^3 - 4x^2 - x + 1 = (x-2)^3\)