Answer:
234
Step-by-step explanation:
We want to find the summation from n = 2 to n = 10 of the equation -4 + 5n.
We can use the summation formula:
[tex]S=\frac{(a_1+a_n)*n}{2}[/tex], where a1 is the first term, [tex]a_n[/tex] is the last term, and n is the number of terms
Here, we can say the first term occurs when n = 2:
-4 + 5n
-4 + 5 * 2 = -4 + 10 = 6
The last term will be when n = 10:
-4 + 5n
-4 + 5 * 10 = -4 + 50 = 46
The number of terms is just 10 - 2 + 1 = 9 terms.
Substitute these in:
[tex]S=\frac{(a_1+a_n)*n}{2}[/tex]
[tex]S=\frac{(6+46)*9}{2}=\frac{468}{2} =234[/tex]
Thus, the answer is 234.
