### Home > PC > Chapter 12 > Lesson 12.1.3 > Problem 12-30

12-30.

Juanita wants to solve the following problem using matrices, but is not sure how. Homework Help ✎

The cost of 2 pencils, 2 pens, and 2 erasers is $2.46. The cost of 2 pencils, 5 pens, and 1 eraser is $4.38. The cost of 1 pencil, 1 pen, and 2 erasers is $1.38. Find the cost of each item.

Explain what she should do.

Solve this problem.

Think about how you would write an equation for each sentence.

What would your system of equations look like?

How could you write your system as a matrix equation instead?

Where *x* = cost of 1 pencil, *y* = cost of 1 pen, *z* = cost of 1 eraser.

Solve for *x*, *y*, and *z* using your calculator.See problem 12-19 if you need more help.