1)

Browser-based, real-time TeX, LaTeX and ASCIIMath visualization

Need to find common ratio(q), also I know that geometric progression is decreasing.

2)Browser-based, real-time TeX, LaTeX and ASCIIMath visualization...

Need to find x, I left left side and instead of right side I wrote geometric progresison sum formula but didn't get a result.

3)

Browser-based, real-time TeX, LaTeX and ASCIIMath visualization

Need to find from 5th and 10th(inclusive) terms sum.

4) 3 numbers, first one is 5, makes arithmetic progression. If we put 9 instead of first number we would get geometric progression. Need to find these 3 arithmetic progression terms.