First answer gets the brainliest! The closed form sum of

$$12 \left[ 1^2 \cdot 2 + 2^2 \cdot 3 + \ldots + n^2 (n+1) \right]$$
for $n \geq 1$ is $n(n+1)(n+2)(an+b).$ Find $an + b.$

n is an unspecified positive integer.  If you want a single numerical result for the sum you must specify the value for n.

For example:

n = 5    means  n(n+1)(n+2)(3n+1) = 3360

n=9     means   n(n+1)(n+2)(3n+1) = 27720

etc.

The sum is a function of n.

22.83 repeating

step-by-step explanation:

137 ÷ 6 is 22.8333333 therefore we understand that 3 is repeating.

happy to

pls mark as brainliest

a28=58

step-by-step explanation:

a1=a1+(n-1)d

a28= 4+ (28-1)2

a28=4+(27)(2)

a28=4+54

a28=58