SOLUTION: Solving a system of equations word problems using matrices Suppose you invested $10,000, part at 6% annual interest and the rest at 9% annual interest. If you received a total of

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Solving a system of equations word problems using matrices Suppose you invested $10,000, part at 6% annual interest and the rest at 9% annual interest. If you received a total of      Log On


   

Question 1159505: Solving a system of equations word problems using matrices
Suppose you invested $10,000, part at 6% annual interest and the rest at 9% annual
interest. If you received a total of $684 in interest after one year, how much did you
invest at each rate?
Found 2 solutions by Boreal, greenestamps:
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
not using a matrix unless one wants to make a table
x at. 6% for .06x
10000-x at 9% for 900-.09x
.06x+900-.09x=684
-.03x=-216
x=7200 @ 6% for $432
10000-x=2800@9% for $252

Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


Gauss-Jordan elimination?
Cramer's Rule?
or maybe something else?

Just specifying "using matrices" doesn't tell us what method of solution you want to use.