Question

How many terms of A.P. 9,17,25....add upto 636​

Answer 1

Answer:

12

Step-by-step explanation:

a=9; d=8; 5=636

n/2 [2a+(n-1)d]

n/2[2(9)+(n-1)8]

n/2[2(9)+(n-1)8]

n/2[18+8n-8]

636=n/2=[8n+10

4n2+5n-636=0

4n2+(53-48)n-636=0

4n2+53n-48n-636=0

4n(n-12)+53(h-12)=0

(h-12)4n+53)=0

by zero product

h-12=0

h=12

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