What's the domain of square root of (x^2-81)

Asap describe the transformations required to obtain the graph of the function f(x) from the graph of the function g(x). f(x)=-5.8sin x. g(x)=sin x. a: vertical stretch by a factor of 5.8, reflection across y-axis. b: vertical stretch by a factor of 5.8,reflection across x-axis. c: horizontal stretch by a factor of 5.8, reflection across x-axis. d: horizontal stretch by a factor of 5.8 reflection across y-axis.

What is the value of m in the equation 1/2 m - 3/4n=16 when n=8

Amachine part consists of a half sphere and a cylinder, as shown in the figure. the total volume of the part is π cubic inches.