Find the area of the region under the graph of the function $f$ on the interval $[0,6]$. \[ f(x)=6 x-x^{2} \] square units

Step 1 ：The area under the curve of a function from a to b is given by the definite integral of the function from a to b. In this case, we need to find the definite integral of the function \(f(x)=6x-x^2\) from 0 to 6.

Step 2 ：The area under the curve of the function \(f(x)=6x-x^2\) from 0 to 6 is 36 square units.

Step 3 ：Final Answer: The area under the curve of the function \(f(x)=6x-x^2\) from 0 to 6 is \(\boxed{36}\) square units.