Try another version of this question Give the domain of `r(x) = sqrt(6-x)` in interval notation.
Box 1: Enter your answer using interval notation. Example: [2,5)
Remember that, when we are working with real numbers, the number in an even root must be non-negative (i.e. `>= 0`)
Use U for union to combine intervals. Example: (-oo,2] U [4,oo)
Enter each value as a number (like 5, -3, 2.2172) or as a calculation (like 5/3, 2^3, 5+4)
Enter DNE for an empty set. Use oo to enter Infinity. `(-oo,6]`