Atriangle has a side lengths of (5.5x + 6.2y) centimeters, (4.3x+8.3z) centimeters and (1.6z -5.1y) cenrimeters which expression represents the perimeter, in centimeters of the triangle

How is working backward similar to solving an equation?

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.

For f(x) = 3x+1 and g(x) = x2 - 6, find (g/f)(x)