# Thread: Equation and inverse function problems

1. ## Equation and inverse function problems

solve for:

9^x -5 x 3^x +6= 0

i've been trying to solve for this in which i have let U equal 3x and then by using the null factor law work out the answer. but somehow i didn't get the right answer :L

and also for:

Find the inverse function of

y=loge (x + 1) -2

in which i did

x= loge (y +1 ) -2

then x -2 = loge ( y+1)

but i seemed to get the wrong answer.

any help would be greatly appreciated!!

2. ## Re: need help with math questions

Originally Posted by kiimberly2
solve for:

9^x -5 x 3^x +6= 0

i've been trying to solve for this in which i have let U equal 3x and then by using the null factor law work out the answer. but somehow i didn't get the right answer :L

and also for:

Find the inverse function of

y=loge (x + 1) -2

in which i did

x= loge (y +1 ) -2

then x -2 = loge ( y+1)

but i seemed to get the wrong answer.

any help would be greatly appreciated!!
for the first one take $3^x=y$. Then $9^x=y^2$. Your problem boils down to solving a quadratic.

3. ## Re: need help with math questions

Find the inverse function of

y=loge (x + 1) -2

in which i did

x= loge (y +1 ) -2

then x +2 = loge ( y+1)

but i seemed to get the wrong answer.

any help would be greatly appreciated!!
You're almost there after making the change shown in the quote. Solve this equation for y.

4. ## Re: need help with math questions

Notice the logarithmic function is the inverse function of the exponential function.