Question

The sum of the first n consecutive even numbers can be found using S = n2 + n, where n ≥ 2.

Answer 1

Answer:

Value of n when sum is 156 is 12

Step-by-step explanation:

Given: function to find sum of first n consecutive even numbers, S = n² + n where n ≥ 2

To find: value of n when Sum = 156

Consider, the function

S = n² + n

156 = n² + n

n² + n - 156 = 0

n² + 13n - 12n - 156 = 0

n ( n + 13 ) - 12 ( n + 13 ) = 0

( n + 13 )( n - 12 ) = 0

So, n + 13 = 0    nd     n - 12 = 0

⇒ n = -13    and  n = 12

n cannot be less than 2, So, value of n = 12

Therefore, Value of n when sum is 156 is 12

Answer 2

The following are the choices on this question:
 A.6
 B. 39
 C. 26
 D. 12   
The answer is option D. 12.

Check this out:
S=n² + n
S= 12² + 12
     (you can get the square of 12 by multiplying 12 by itself: 12 × 12)
S=144 +12
S=156