# What is the range of the function f(x)=-4cos(2x - 3)?

The range is $\left[- 4 , 4\right]$.
Since $2 x - 3$ can be any real number, the range of $- 4 \cos \left(2 x - 3\right)$ can be determined by expanding the range of $\cos \left(x\right)$ by a factor of $4$.