The answer is 68 because 10 multiplied by 5 is 50 plus 18 is 68
Answer:
The solution for this system is: 
Step-by-step explanation:
The problem states that we have to solve this system by the elimination method
In the elimination method, we transform the system in such a way that one variable can cancel each other. With this, we find the result of the other variable. Then, we can replace the variable we found in any of the equations, and we have the value of the variable that we had initially canceled.
In this problem, we have the following system:


If we add equations 1) and 2), the variable x is going to be eliminated





Now, we can replace the value of y in any of the equations, to find x:
I will replace in equation 2)





The solution for this system is: 
Step-by-step explanation:

The simplest method is "brute force". Calculate each term and add them up.
∑ = 3(1) + 3(2) + 3(3) + 3(4) + 3(5)
∑ = 3 + 6 + 9 + 12 + 15
∑ = 45

∑ = (2×1)² + (2×2)² + (2×3)² + (2×4)²
∑ = 4 + 16 + 36 + 64
∑ = 120

∑ = (2×3−10) + (2×4−10) + (2×5−10) + (2×6−10)
∑ = -4 + -2 + 0 + 2
∑ = -4
4. 1 + 1/4 + 1/16 + 1/64 + 1/256
This is a geometric sequence where the first term is 1 and the common ratio is 1/4. The nth term is:
a = 1 (1/4)ⁿ⁻¹
So the series is:

5. -5 + -1 + 3 + 7 + 11
This is an arithmetic sequence where the first term is -5 and the common difference is 4. The nth term is:
a = -5 + 4(n−1)
a = -5 + 4n − 4
a = 4n − 9
So the series is:

Answer:
a the first one
Step-by-step explanation:
1/11 means 1 divided by 11