+33658 If x>15/6 then the term in brackets is negative and f(x) would be complex, so if we are dealing with the Real numbers only, then the domain is -infinity to 15/6 (2.5).
f(x)= (15-6x)^1/2
Note that we cannot take the square root of a negative number.....thus
15 - 6x must be greater than or equal to 0....therefore
15 - 6x >= 0 add 6x to both sides
15 >= 6x divideboth sides by 6
15/6 >= x
In other words, x <= 15/6 and reducing x <= 5/2 .... or x <= 2.5
Here's the graph: https://www.desmos.com/calculator/adyhteclth
