Question

let f(x)=sr9xand g(x)=x-5. whats the smallest number ofthe domain of (f0g)?

Answer 1

The answer is 5. fog is just the function g(x0 substitued to the x of f(x) thus, \[fog = \sqrt{9(x-5)}\] then find the least value of x that can be substituted that is, what can make the thing inside the square root real. This the thing inside must be at least 0 therefore\[9(x-5)\ge0 \] then \[x \ge 5\]