What number comes next?
2,7,8,3,12,9

The first, third and fifth number are even numbers. 2, 8, 12

And the second, forth and sixth numbers are odd numbers. 7, 3, 9 

1. y = c + 2x

c1= 2 (and subsequent c= next number in the series) and x is in reducing order:

2 + 2x3 = 8

8 + 2x2 = 12

12 + 2x1 = 14 

2.  u = a (+-) 2(v).   

a1=7 (and subsequent a= next number in the series) and v is in increasing order.

7 - 2x2 = 3

3 + 2x3 = 9

9 - 2x4 = 1 

the subsequent number is an even number, so it should be 14

replace   with   27   and simplify.

10 , 27 , 10 , 70 , 10 , 35 , 10 , 48

step-by-step explanation:

answer: c

substitute in the values.

for a:

f(0) = 0 + 9

f(0) = 9

a is a solution.

for b:

f(7) = 14 + 9

f(7) = 23

b is a solution.

for c:

f (3) = 6 + 9

f(3) = 15

c is not a solution. it's supposed to be 14.

for d:

f(2) = 4 + 9

f(2)= 13

d is a solution.