Write out how you use substitution to solve a system of equations.

The mean temperature for the first 4 days in january was 7°c. the mean temperature for the first 5 days in january was 5°c. what was the temperature on the 5th day?

Answer this question only if you know the answer! 30 points and

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.