Introduction to rate law

The rate law for a particular reaction is $\text{rate}=k[\mathrm{X}{]}^2$‍. In an experiment, the initial rate of the reaction is determined to be $0.080\text{mol}/(\text{L}\cdot \text{s})$‍ when the initial concentration of $\mathrm{X}$‍ is $0.20\text{mol}/\text{L}$‍.