Question

simplify 1/9 - 1/x all over 1/81 - 1/x^2

Answer 1

9x/ (x + 9)

Answer 2

thanks!! but could you tell me how you got that?

Answer 3

The common denominator for the first two fractions is 9x.
x/9x - 9/9x which would give you: (x-9)/9x

For the second pair of fractions, your common denominator is 81x^2
x^2/81x^2 - 81/81x^2 which would give you (x^2 - 81)/81x^2

Set up the division: (x-9)/9x ÷ (x^2 - 81)/81x^2
When dividing fractions, you change the division sign to multiplication and invert the second fraction

{(x-9)/9x} * {81x^2 / (x^2 - 81) } = {(x-9)/9x} * {81x^2 / (x - 9) (x + 9) }

Now you can cancel the (x-9) on top and bottom:
81x^2 / { 9x (x + 9)}

Reduce the top and bottom by 9x to get: 9x / (x+9)

Answer 4

thanks!! could you help with another one?

Answer 5

yeah close this ans start another