can you help me with this?

Question

some students find the process of solving three variables using cramer's rule rather tedious. is there a way of speeding up this process, like perhaps using cramer's rule to find the value of the only one of the one variables? describe how this process might work, presenting a especific example together with your description. remember that your goal is still to find the value of each variable in the system.

please..... i've it all over again but i really cant.....
please help me......

Answer 1

While there are MANY ways you can solve a 3 x 3 system of equations, Cramer's Rule is actually about the easiest--assuming you have some sort of technology (such as a graphing calculator) to work out the determinants. If you are trying to find all those 3 x 3 determinants by hand, it's tedious indeed. Unfortunately it's still easier than most other methods for solving systems of equations.

The exception would be if you have missing variables in one or more of the equations. Then you could likely use substitution or linear combination to find two of the variables and substitute to find the third.

Some graphing calculators (like a TI-86 or a Casio 9850) will solve systems of equations directly. On the TI-86 you want the "SIMULT" (simultaneous equations) solver, while on the Casio you'd choose "EQUA" and then "Simultaneous". In both cases, you just enter the coefficients of the equations and hit "SOLVE" to get the answers.