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## Ajay Kumar Muchakurthi is teaching live on Unacademy Plus

Ajay Kumar Muchakurthi

Plus Educator, Expertise in Current Affairs, Governance, Science and Technology, Internal Security & Disaster Management

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Rashmita Bindhani

a year ago

hllo mam can u explain how u used dat formula in q6 n(n-1)+n(n+1)......=b

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Binati Sheth

a year ago

Consecutive numbers as in numbers that come next to each other in order like 11, 12, 13. Now I can assume x = 11, so 12 = x+1, 13 = x+2.... I can also assume x= 12 so, 11=x-1 and 13 = x+1.... So, to make things simpler as in to get + and - x and 1, we generally assume consecutive numbers as ...x-2, x-1, x, x+1, x+2... Here, our roots are consecutive. Let the roots be x-1, x, x+1... so, with powers of 3, ax3 + bx2 + cx + d = 0, sum of roots = (x-1+x+x+1)= -b/a..... product of roots = (x-1)(x+1)x = -d/a..... and sum of products = (x-1)x + (x-1)(x+1) + (x+1)x = c/a....... Insert these values in our question and you'll get the equation