Find the number that makes the ratio equivalent to 1: 7. 8: ?

If f(x)=2x-6 and g(x)=3x+9, find (f-g)(x)

What is the value of x in the following equation? -3x-2=2x+8

Which of the expressions (on the photo document i inserted) together represent all solutions to the following equation? 8cos(12x)+4=-4 *the answer should be in degrees.* > i would like for someone to explain the process to find the solutions for this.