Respuesta :

Answer:

40

112

2n^2 + 2n       C

Step-by-step explanation:

a)The correct formula is 2n^2 + 2n

So for n =4, the answer is

2*4^2 + 2*4

2*16 + 8

32 + 8

40

b) For the seventh answer you get

2 * 7^2 + 2*7

2*49 + 14

98 + 14

112

c) The correct formula to use is

2n^2 + 2n  See diagrams for the number of matchsticks to be used.

n                    2n^2 + 2n

1                    2*1^2 + 2*1

1                    2 + 2

1                    4

2                    2*2^2 + 2*2

2                    2* 4 + 4

2                    8 + 4

2                    12

3                    2*3^2 + 2*3

3                    18 + 6

3                    24

What an extremely interesting sequence. I'll bet not one person in 100 could get this without the match stick diagrams.  I'm sorry I didn't read the question more carefully.