The 7th term in the expansion of \((a+bx)^{12}\) in ascending powers of \(x\) is \(924x^6\). It is given that \(a\) and \(b\) are positive constants.

(i) Show that \(b=\dfrac1a\).

The 6th term in the expansion of \((a+bx)^{12}\) in ascending powers of \(x\) is \(198x^5\).

(ii) Find the value of \(a\) and of \(b\).