2.  A basic equation is made of three parts, coefficients, variables, and the constants.  The coefficient is the number before the variable  The variable is the letter of which you are trying to find the value  And the constant is what the equation is equal to.

3.  7x+5y=3  3x-2y=22  To find the answer to these equations you can use matrices.  The coefficients go in one matrix, you multiply that by the variable matrix, and then set the two equal to the constants.

4.  7x+5y=3  3x-2y=22

5.  To solve without a calculator you must first find the inverse:

8.  Is then (4,-5)  Aren’t you glad you have a TI calculator?  You don’t ever have to do that long process ever again!

9.  Click:  2 nd  Matrix  Edit  A  Put in dimensions for the equation (2x2 3x3, etc) under A (use 2x2 for this example)  Type in the coefficient matrix as it appears.

10.  Repeat the first three steps except put the constant matrix under B.  Exit out of the matrix (2 nd, quit)  Then click 2 nd, and then Matrix  Select A  Then hit the “x-1” button to get the inverse  Then multiply that by the matrix B  And Voila! You have your X and Y!  Make sure when you are typing in the numbers for your matrices that the dimensions are correct, the number of columns goes first, then the number of rows.

11.  Solve:  8x+3y-65z=46  6y+18z=34  21x+40y=89z+12  HAVE FUN!

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