Homework: Pg 195 #39-47, 55a

SEC 7: SOLVING SYSTEMS OF EQUATIONS WITH MATRICES

Learning Target: I will solve systems of equations in mathematical and real-world situations using matrices.

Review: Quality Core Practice

Ex 1: The Identity Matrix Multiply the following matrices: a. 1 0 0 1 2 3 −4 1 = b. 1 0 0 0 1 0 0 0 1 2 0 −5 −3 1 1 4 12 7 = What happened when you multiplied a matrix by the Identity Matrix?

Watch the KornKast video and take notes here.

Generic Example Example with Numbers

Ex 2: Write each system as a matrix equation and solve.

A. B.

Ex 3: Shopping!

 A linen shop has several tables of sheets and towels on special sale. The sheets are all priced the same and so are the towels. Mario bought 3 sheets and 5 towels at the cost of $137.50. Marco bought 4 sheets and 2 towels at the cost of $118.00. Find the price of each item.

Ex 4: Happy Holidays!

 Suppose you want to fill nine 1-lb tins with a holiday snack mix. You plan to buy almonds for $2.45/lb, peanuts for $1.85/lb and raisins for $.80/lb. You have $15 and want the mix to contain an equal amount of nuts to raisins. How much of each ingredient should you buy?

HOMEWORK  Pg 195 #39-47, 55a - due Friday if we don’t finish the notes today.

* Use inverse matrices to solve each system of equations.