# Thread: [SOLVED] finding inverse formulas

1. ## [SOLVED] finding inverse formulas

i can find the inverse of a function, but im having trouble finding the formulas in these problems

Find a formula for the inverse of the function.
y = 8x^3 + 7

Find a formula for the inverse of the function. y = ln(x + 8)

2. Originally Posted by kyleu03
i can find the inverse of a function, but im having trouble finding the formulas in these problems

Thank you!

3. Originally Posted by kyleu03
i can find the inverse of a function, but im having trouble finding the formulas in these problems

Find a formula for the inverse of the function.
y = 8x^3 + 7

Find a formula for the inverse of the function. y = ln(x + 8)
Why don't you apply your knowledge to the first problem? It's not really any different.

$

y = 8x^3+7
$
$x = 8y^3+7$
$x-7 = 8y^3$

Take the cube root.

$y = \sqrt[3]{\frac{(x-7)}{8}
}$

4. Originally Posted by A Beautiful Mind
Why don't you apply your knowledge to the first problem? It's not really any different.

$

y = 8x^3+7
$
$x = 8y^3+7$
$x-7 = 8y^3$

Take the cube root.

$y = \sqrt[3]{\frac{(x-7)}{2}
}$

thats wrong...

5. Originally Posted by kyleu03
thats wrong...
the /2 should be /8

but thanks

6. still cant figure out
y = ln(x + 8)