Find a probable next term for the sequence 9,20,39,72,125,204,315

464

Step-by-step explanation:

The first term is 9.

The difference between the second and first term = 20 - 9 = 11

The difference between the third and second term = 39 - 20 = 19

The difference between the fourth and third term = 72 - 39 = 33

The difference between the fifth and fourth term = 125 - 72 = 53

The difference between the sixth and fifth term = 204 - 125 = 79

The difference between the seventh and sixth term = 315 - 204 = 111

The differences are 11, 19, 33, 53, 79, 111

From the difference: 19 - 11 = 8, 33 - 19 = 14, 53 - 33 = 20, 79 - 53 = 26, 111 - 79 = 32

We can see from the first difference (8), if we add 6 we get 14, if we add another 6 we get 20, if we add 6 we get 26, if add 6 we get 32

We get the eight term using:

32 + 6 = 38

let x be the difference between the eight term and the seventh term, hence:

x - 111 = 38

x = 111 + 38

x = 149

Therefore:

eighth term - seventh term = 149

eighth term - 315 = 149

eighth term = 149 + 315

eighth term = 464

The next probable term is 464

d i think

step-by-step explanation:

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!