4. Represent the following situation mathematically

A train travels a distance of 630 \(km\) at a uniform speed. It would have taken 1 hour more to cover the same distance if the speed had been 3 \(km/h\) lesser than the uniform speed. We need to find the speed of the train.

 

 

[Note: Enter the equation without simplification, and enter the sign and coefficient in separate boxes.]