How do you solve he formulas for numbers 9 and 10?

9)

t = V+K/g, n=multiply both side by g to get :

TG = V+K

 now divide both sides by T to get G alone

 so G = V/t + K/t = g = (V+K)/t

10)l = -a +2S/2

see explanation

step-by-step explanation:

since the sequence is geometric there is a common ratio r between consecutive terms, that is

r = 4 ÷ - 2 = - 2

r = - 8 ÷ 4 = - 2

r = 16 ÷ 8 = - 2

the next term - 13 must be incorrect as it should be - 32 for the sequence to be geometric.

the first 4 terms are therefore geometric with common ratio r = - 2