Evaluate 3r(t-v) if r=2, t=6, and v=4

Prove that the sum of two consecutive exponents of the number 5 is divisible by 30.if two consecutive exponents are 5n and 5n + 1, then their sum can be written as 30.

Find the domain of the following expression: 1/(√x)-2

F(x) = 1/x g(x)=x-4 can you evaluate (g*f)(0) ? why or why not?