What is a calorimeter?

In an experiment to determine the specific heat capacity of a solid, following observations were made :

Mass of calorimeter $+$ stirrer $=x \mathrm{kg}$
Mass of water$=y \mathrm{kg}$
Initial temperature of water $=t_1{}^{\circ }\mathrm{C}$
Mass of solid $=z \mathrm{kg}$
Temperature of solid $=t_2{}^{\circ }\mathrm{C}$
Temperature of mixture $=t°\mathrm{C}$

Specific heat capacity of calorimeter and water are $c_1$ and $c_2$ respectively. Express the specific heat capacity $c$ of the solid in terms of the above data.

A heater of power $P$ watt raises the temperature of $m \mathrm{kg}$ of a liquid by $\Delta T \mathrm{K}$ in time $t \mathrm{s}.$ Express the specific heat capacity of liquid in terms of above data.