elimination



Hi Coribabee:

You have choices.

If you want to eliminate the x-variable, then you could multiply the first equation by -5 and also multiply the second equation by -2. Then you'll have two equations where the 10x and -10x will cancel when added.

If you want to eliminate the y-variable, then you could multiply the second equation by 3. Then you'll have two equations where the 3y and -3y will cancel when added.

(There are even more choices to eliminate the x-variable or y-variable; some involve fractions.)

You choose.

If you need more help, then please post your work, and try to say something about why you're stuck.

Cheers,

~ Mark :)

 
coribabee said:
can anyone help me?? i dont what to multiply by
{2x+3y=12............................................(1)
{5x-y=13..............................................(2)
Click to expand...

If I were to do this problem (solving for x & y - you did not explain what you wanted to do)

I would eliminate 'y' by multiplying eqn. (2) by 3 and add to eqn. (1)

Please show us your work, indicating exactly where you are stuck - so that we know where to begin to help you.
 
coribabee said:
can anyone help me?? i dont what to multiply by
{2x+3y=12
{5x-y=13
Click to expand...
After multiplying 2nd equation by 3, you have:
2x + 3y = 12
15x- 3y = 39

If you can't "see" what to do now, you need classroom help.
 
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