SOLUTION: If a+b=15, a+c=16, and b+c=11, how do you get a b and c on the calculator?

Algebra ->  Matrices-and-determiminant -> SOLUTION: If a+b=15, a+c=16, and b+c=11, how do you get a b and c on the calculator?      Log On


   

Question 334985: If a+b=15, a+c=16, and b+c=11, how do you get a b and c on the calculator?
Found 2 solutions by stanbon, Edwin McCravy:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
If a+b=15, a+c=16, and b+c=11, how do you get a b and c on the calculator?
-----
You can't.
Your calculator is a numerical calculator;
it is not a symbolic calculator.
-------------------
Cheers,
Stan H.

Answer by Edwin McCravy(20086) About Me  (Show Source):
You can put this solution on YOUR website!
 
system%28a%2Bb=15%2C%0D%0Aa%2Bc=16%2C%0D%0Ab%2Bc=11%29

Write it this way, so that all letters appear in all equations and
every letter has a coefficient showing:

system%281a%2B1b%2B0c=15%2C%0D%0A1a%2B0b%2B1c=16%2C%0D%0A0a%2B1b%2B1c=11%29

On you TI-83 or TI-84,

Press ON
Press CLEAR

Press 2nd
Press x-1  (MATRIX)
Press right arrow key twice to highlight EDIT
Press 1
Press 3
Press ENTER
Press 4
Press ENTER

Press 1
Press ENTER
Press 1
Press ENTER
Press 0
Press ENTER
Press 15
Press ENTER
Press 1
Press ENTER
Press 0
Press ENTER
Press 1
Press ENTER
Press 16
Press ENTER
Press 0
Press ENTER
Press 1
Press ENTER
Press 1
Press ENTER
Press 11
Press ENTER

Press 2nd
Press MODE (QUIT)

Press 2nd
Press x-1  (MATRIX)
Press right arrow key to highlight MATH
Press ALPHA
Press APPS

You should see  rref(

Press 2nd
Press x-1  (MATRIX)
Press 1
Press ENTER

You should see 

rref([A]
    [[1 0 0 10]
     [0 1 0 5 ] 
     [0 0 1 6 ]]

The answers are a=10, b=5, c=6   

Edwin