What is the range of trigonometric function y=-4*sin(51x+pi)?

The range of a function is all the real values that f(x)
can take for values of x that lie in the domain.

y =
-4*sin(51x + pi)

Here x can take values in (-inf., inf.)
but for any value of x, sin(51x + pi) can only lie in the interval [-1 ,
1]

=> y = -4*sin(51x + pi) lies in the interval [-4
, 4]

The range of y = -4*sin(51x + pi) is [
-4 , 4]