C(a + b)- d = f, for a

Step-by-step explanation:

C(a + b) = f + d

a + b = (f + d)/C

a = (f + d)/C - b

y = 2x

step-by-step explanation:

if you divide each number in the sequence, you'll see that they all have a multiple factor of 2. each number in the series, and any other numbers which may continue, will be multiplied by 2. therefore, y is the next number in the sequence, and x is the current one, so, our formula will be y = 2x.