### Home > INT3 > Chapter 9 > Lesson 9.1.4 > Problem 9-56

9-56.

Consider the system of equations

*y*= cos(*x*) and*y*= –1.*9-56 HW eTool*(Desmos). Homework Help ✎Is it possible to solve this system by substitution? By the Elimination Method? By graphing?

List at least five possible solutions.

Consider the list of solutions you wrote in part (b) as a sequence and write an equation to represent

*all*possible solutions.

Use substitution: cos(*x*) = −1. Solve for *x*.

List five values where the graphs intersect.

List your values from part (b) in order and look for a relationship.

*x* = (−180 + 360*n*)° for all integers *n*

Use the eTool below to help answer parts (a) and (b).

Click the link at right for the full version of the eTool: *INT3 9-56 HW eTool*