If a =2^2 × 3^x, b =2^2 × 3 × 5, c =2^2 × 3 × 7 and LCM ( a, b, c )=3780, then x is equal to

If $\displaystyle \mathrm{a}=2^{2} \times 3^{x}, \mathrm{~b}=2^{2} \times 3 \times 5, \mathrm{c}=2^{2} \times 3 \times 7$ and $\displaystyle \mathrm{LCM}(\mathrm{a}, \mathrm{b}, \mathrm{c})=3780$, then $\displaystyle x$ is equal to