I'm learning very basic diffeqs in another math class, and the type of problems were doing are first order separable differential equations, very basic stuff.

I'm trying to use Mathematica/Wolfram Alpha to check my answers, but everytime, wolfram will output the incorrect answer and I will always have the correct answer and I can't figure out why

For example:

I calculated y to be:

When simplified, this matches the back of my book. Great. When I type the same problem for Wolfram Alpha to solve, I get back this:

Input:

Solve

Output:

Which is completely wrong. Could this be a bug in the CAS?