$-3$rd degree polynomial with coefficients a $=1\mathrm{.}5$; b $=5$; c $=25$; d$1$ is used for iterative computation using Newton's method, where a$,$ b$,$ c and d are coefficients of f$($s$)=$ as$^3+$ bs$^2+$ cs $+$ d

If the measured sensor response is S $=22$ and the initial guess is S$2\mathrm{.}5,$ then how many iterations will be required before Newton Algorithm stops? What is the stimulus value at this point?