subtract
2over 49z^3y - 1over 14z^2y
answer should look something like _-7z over_z^3y
(a number should be in the _ part of the example answer)

Question

subtract
2over 49z^3y - 1over 14z^2y
answer should look something like _-7z over_z^3y
(a number should be in the _ part of the example answer)

anonymous · Answer

like 5 over 9z^3y - 1 over 15z^2y = 25-3z over 45z^3y

anonymous · Answer

First you have to find a common denominator, which you can do by multiplying the denominators together, and then cross-multiplying for the numerators.

anonymous · Answer

After that you can just subtract the numerators and write the result of that over the common denominator.

anonymous · Answer

so the common denominator is 7 right?

anonymous · Answer

or 98?

anonymous · Answer

Okay, here's what I got (it's late here, so be patient haha)

So you start out with 2/49z^3y - 1/14z^2y

Cross-multiplying provides

28z^2y/(686z^3yz^2y) - 49z^3y/(686z^3yz^2y)

anonymous · Answer

Then you can cancel out a z^2y from all the numerators and denominators.

28/686z^3y - 49z/686z^3y

So combining the fractions you get

(28 - 49z)/686z^3y

anonymous · Answer

You can probably simplify the constants :P