# Math Help - log question

1. ## log question

Don't really know where to start on this one.

Find all real solutions.

$log_{2}(x-2) + log_{2}(x+1) = log_{2}10$

2. Originally Posted by smplease
Don't really know where to start on this one.

Find all real solutions.

$log_{2}(x-2) + log_{2}(x+1) = log_{2}10$
Here's a start:

Use $log_a (x) + log_a (y) = log_a (xy)$

You can then remove the logs and solve for x.

3. Originally Posted by smplease
Don't really know where to start on this one.

Find all real solutions.

$log_{2}(x-2) + log_{2}(x+1) = log_{2}10$

$\log_{2}(x-2) (x+1) = \log_{2}10$

$(x-2) (x+1) = 10$

4. I got

$x^2 - x -12 = 0$

$(x+3)(x-4) = 0$

x = -3, or
x = 4

Have I gone to far?

Thanks for your help guys

5. Originally Posted by smplease
I got

$x^2 - x -12 = 0$

$(x+3)(x-4) = 0$

x = -3, or
x = 4

Have I gone to far?

Thanks for your help guys
Thats exactly what you need!