when I triple a number and add 20 i will get 5he same answer as i do when i subtract the number from 40 find the number

sorry this example

Let that certain number be x.

3x + 2 = 50 - x

3x + x = 50 - 2

4x = 48

x = 48/4

x = 12

That certain number is 12.

In a geometric sequence, we have a multiplier to get the next term's value, namely, if we want to know what the 6th term is, that'll be 120 * the multiplier.

the multiplier is so-called the "common ratio", so if say the value for the common ratio is "r", then the 6th term is 120*r, and the 7th term is 120*r*r or just 120r².  Now, we know the 7th term is 30, thus