Question

If the sum of first n' successive even natural numbers is 72 then formulate the quadratic equation to find 'n'.

Answer 1

Step-by-step explanation:

Even Natural numbers are : 2,4,6,8... and so on till infinity.

So our A.P (Arithmetic Progression) is =2,4,6,8,...

So, a ( first term) = 2, d = 2

Sn=n/2[ 2a + (n-1) × d ]

72= n/2 (2a + dn - d)

72 = n/2 (2×2 + 2n - 2)

72 = n/2 (2 + 2n)

72 = 2n/2 + 2n×n

72 = n + 2n×n

Final Answer:

2n×n + n - 72 = 0