Make each layer y meters below the ground and X layer above the ground.

Yes: 2y+3(x- 1)=25.

When y=2, 5, 8, x is an integer, and 5, 8 does not match the meaning of the question.

Therefore, 2*2+3(x- 1)=25, x=8,

So: take the elevator from the -2 floor and go up 25 meters to the 8 th floor, marked +8.

I wish you progress in your studies and go up a storey still higher! (*^__^*)