How many terms of the AP:63,60,57,...must be added so that tgeir sum is 693? Explain the double answer
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a=63
d=3
Sn=693
Sn=n/2(2a+(n-1)d)
693=n/2(2*63+(n-1)3)
693=n/2(126+3n-3)
693*2=n(126+3n-3)
1386=126n+3n²-3
1386+3=126n+3n²
1389-126n-3n²=0.
d=3
Sn=693
Sn=n/2(2a+(n-1)d)
693=n/2(2*63+(n-1)3)
693=n/2(126+3n-3)
693*2=n(126+3n-3)
1386=126n+3n²-3
1386+3=126n+3n²
1389-126n-3n²=0.
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