Simplify

[shide]

Total math newb. Sorry.

I have to simplify:
18x^7y^8/45x^10y


I worked out;
2x^7y^8/5x^10y = 2y^7/5x^-3

But the answer is 2y^7/5x^3.

I'm missing something here. 7-10 is negative 3. But the answering power is not negative 3. I can't see where the negatives cancel out?

 

[lev888]

Total math newb. Sorry.

I have to simplify:
18x^7y^8/45x^10y


I worked out;
2x^7y^8/5x^10y = 2y^7/5x^-3

But the answer is 2y^7/5x^3.

I'm missing something here. 7-10 is negative 3. But the answering power is not negative 3. I can't see where the negatives cancel out?

`x^7/x^10 = 1/x^3 = x^-3`

 

[Steven G]

There are more factors of x's in the denominator, so the power of x in the denominator should be positive.

A note about your notation, [math]2y^7/5x^{-3} = \dfrac{2y^7x^{-3}}{5}[/math]
I suspect that you meant to write 2y^7/(5x^(-3)) = [math]\dfrac{2y^7}{5x^{-3}}[/math]

 

[alejano]

hi, sorry for my english.

why y^7 is right ? because you did 8 minus 1 , and the result is in the numerator.
So, if you do 7 minus 10 you get -3. but why, although, you put the result in the denominator?


the solution is (2 y^7 x^-3)/5, and that negative exponent you could convert to a positive exponent if you change his place
in the fraction: from up to down. so you get (2 y^7)/(5 x^3)
i hope i have helped you.