10,000+15x=9000 is the answer
Times as many means multiply
hope this helps
When n = 1 first term = -6
n = 2 second term = 0
n = 3 third term = 6
n = 4 4th term = 12
so we have an Arithmetic sequence first term = -6 and common difference = 6
Sum 14 terms = (14/2)[2*-6 + (14-1)*6]
= 462 answer
