Can someone explain me how to do this? No answers, just explanation how to solve. Click on the picture to see the question.​

Since you did not want the answer the things you need to solve this question are below.

Step-by-step explanation:

In order to solve this, you will need to read about the scale factor. Here is a picture telling about it briefly.

= 5

step-by-step explanation:

to find the 15th term substitute n = 15 into the nth term formula

= (- 3 × 15 ) + 50 = - 45 + 50 = 5