Sum of 1 to n natural numbers is 36, then find the value of n. Solve the word problem
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a=1 , Sn=36 , d=1 ,
Tn = a+(n-1)d
Tn = 1+(n-1)*1
= 1+n-1
Tn = n
Sn = n/2(a+l)
36 = n/2(1+n)
72 = n*n+n
n*n+n-72 =0
n*n+9n-8n-72=0
n(n+9)-8(n+9) = 0
(n+9)(n-8) = 0
then
n+9 = 0 , or. n-8 = 0
then
n = -9 , n = 8
then we know n will be positive
n = 8
hope it's help u
Tn = a+(n-1)d
Tn = 1+(n-1)*1
= 1+n-1
Tn = n
Sn = n/2(a+l)
36 = n/2(1+n)
72 = n*n+n
n*n+n-72 =0
n*n+9n-8n-72=0
n(n+9)-8(n+9) = 0
(n+9)(n-8) = 0
then
n+9 = 0 , or. n-8 = 0
then
n = -9 , n = 8
then we know n will be positive
n = 8
hope it's help u
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