You are right!!!!!!!!!!!!!!!
Answer:
n(n+1)(n+5)/3
Step-by-step explanation:
there is no value, as we don't know n.
but we can create a summary formula/ function definition :
this is the sum for k = 1 to n of k×(k+3)
k×(k+3) = k² + 3k
so, the overall sum splits into the sum of k² for k=1 to n, and the sum of 3k for k=1 to n.
and the sum of 3k is 3 times the sum of k for k=1 to n.
Σk² for k=1 to n = [n(n+1)(2n+1)]/6
Σk for k=1 to n = n(n+1)/2
3×Σk for k=1 to n = 3×n(n+1)/2
so, we have a function formula
n(n+1)(2n+1)/6 + 3n(n+1)/2 = n(n+1)(2n+1)/6 + 9n(n+1)/6 =
= n(n+1)(2n+1+9)/6 = n(n+1)(2n+10)/6 = n(n+1)(n+5)/3
Three point zero nine eight
Answer:
y = 3x + 6
Step-by-step explanation:
Since the line is parallel, it has the same slope -- 3
y = 3x + b, sub point (1, 9)
9 = 3(1) + b
9 = 3 + b
b = 9 - 3
b = 6
y = 3x + b -- y = 3x + 6
(-2 1) if u look at it this what you get
