Solve the following pair of linear equations by the substitution method. (i) x + y = 14 x – y = 4
(ii) s – t = 3 \(\frac{s}{3} + \frac{t}{2}\) =6
(iii) 3x – y = 3 9x – 3y = 9
(iv) 0.2x + 0.3y = 1.3 0.4x + 0.5y = 2.3
(v)\(\sqrt2x\) + \(\sqrt3y\)=0 \(\sqrt3x\) - \(\sqrt8y\) = 0
(vi) \(\frac{3x}{2} - \frac{5y}{3}\) =-2, \(\frac{ x}{3} + \frac{y}{2}\) = \(\frac{ 13}{6}\)
If \(\frac{d}{dx}f(x) = 4x^3-\frac{3}{x^4}\) such that \(f(2)=0\), then \(f(x)\) is