Q. 3. If 1+2+3+b) (2,3,5,1,xa) 46656+n=36 then find 13 c) (4/9,25,49,121)b) 1296
Set up equation: The sum of the first n natural numbers is given by the formula S=2n(n+1). We know S=36, so we can set up the equation 2n(n+1)=36.
Eliminate fraction: Multiply both sides by 2 to get rid of the fraction: n(n+1)=72.
Solve quadratic equation: Now we need to solve the quadratic equation n2+n−72=0.
Factor equation: Factor the quadratic equation: n+\(9)(n−8) = 0\
Find valid solution: Set each factor equal to zero and solve for n: n+9=0 or n−8=0.
Find valid solution: Set each factor equal to zero and solve for n: n+9=0 or n−8=0.Solving n+9=0 gives n=−9, which doesn't make sense for the sum of natural numbers, so we discard this solution.
Find valid solution: Set each factor equal to zero and solve for n: n+9=0 or n−8=0.Solving n+9=0 gives n=−9, which doesn't make sense for the sum of natural numbers, so we discard this solution.Solving n−8=0 gives n=8, which is a valid solution.
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