Does any one please know of a simple program/calculator on Internet for solving 2- 3 simultaneous equations?

Question

They are very useful. I can do them by hand, but it takes time and there is always the possibility of mistakes

Answer 1

I'll give the steps to do on the calculator, you go from there:

Say you had the following equations:

x+y = 5
3x-y = -1

Press 2nd then x^-1 key, you are in matrix mode:

Hit right arrow key twice

Hit enter

Type 2, then hit enter. Repeat.

Here we type in the coefficients from the original problem:

x + y turns into | 1 1 |
3x - y | 3 -1 |

So, type in 1, then enter. Type 1, then enter. Type 3, then enter. Type -1, then enter.

Now press 2nd then Mode to quit.

Go back into Matrix mode using the steps from above, choose to edit B this time (press down arrow once before hitting enter).

Matrix B is the what is on the right side of the equal signs. This is a 2 x 1 matrix.

Type in 2, enter. Then hit enter again.

Our matrix is going to look like this:

| 5 |
|-1 |

So, type in 5 then enter. Now type in -1 then enter.

Quit again.

Now, go back into the Matrix menu. Press 1.

Press x^-1

Now, go back into the Matrix menu. Press 2.

Press Enter.

The top number is your x solution.

The bottom number is your y solution.

The same principle can be applied to three variables. There you would get a 3 x 3 matrix for A, and a 3 x 1 matrix for B. The math is the same. Inverse of A times B. The solution matrix starts with x on top and ends with z on the bottom.

Answer 2

i would use excel for this.
for an online spreadsheet you could try the google offering.

so, you would need to figure out how to set up matrices in excel and the upload the sheet to google or try doing this right in google.

have not tried this myself however.

one challenge when doing this is that you need to know if you need to work with 2X2 3X3 4X4 or whateverXwhatever matrices before you start all this work. that makes it all very messy.

oh wait. you do mention 2 or 3 so you need a 2X2 setup and a 3X3 setup.

should be doable.