y^-9/y

Could someone help me understand this?

Question

y^-9/y

Could someone help me understand this?

anonymous · Answer

attachment

anonymous · Answer

That answer in the screen shot is what I put, it was wrong of course.

I just don't understand this

mathstudent55 · Answer

The definition of a negative exponent is:

$\large a^{-n} = \dfrac{1}{a^n} $, for $a \ne 0$.

anonymous · Answer

Yeah thank you.. I know that formula, but I don't know what I did wrong with that question.

mathstudent55 · Answer

That's one thing you need to know.
The other thing is division of powers with the same base.

$\large \dfrac{a^m}{a^n} = a^{m - n} $, again, for $a \ne 0$.

mathstudent55 · Answer

Now let's use the second formula first.

anonymous · Answer

I put $$\frac{ 1 }{ 2y ^{9} }$$

mathstudent55 · Answer

$\large \dfrac{y^{-9}}{y}= \dfrac{y^{-9}}{y^1}$

Can you just do the division using the second rule. Don't worry about the negative exponent for now.

anonymous · Answer

Y^-10

anonymous · Answer

1/y^10

mathstudent55 · Answer

You're correct.

anonymous · Answer

Thank you so much !

mathstudent55 · Answer

You're welcome.

anonymous · Answer

I just need to memorize these formulas (or rules) and understand when to implement which

mathstudent55 · Answer

Correct.