How many terms of the AP 26,21,16,11,..... are needed to give the sum 11?
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sum wala formula lagayie term 11 a 26 d 5
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a=26
d=21-26= -5
S=11
S=n/2(2a+(n-1)d)
11=n/2(2×26+(n-1)(-5))
11=n/2(52+(n-1)(-5))
22=n (52-5n+5)
22=n(57-5n)
22=57n-5n²
0=57n-5n²-22
5n²-57n+22=0
5n²-55n-2n+22
5n(n-11)-2(n-11)
(5n-2)(n-11)
By ignoring n=2/5
n=11
d=21-26= -5
S=11
S=n/2(2a+(n-1)d)
11=n/2(2×26+(n-1)(-5))
11=n/2(52+(n-1)(-5))
22=n (52-5n+5)
22=n(57-5n)
22=57n-5n²
0=57n-5n²-22
5n²-57n+22=0
5n²-55n-2n+22
5n(n-11)-2(n-11)
(5n-2)(n-11)
By ignoring n=2/5
n=11
hipsterizedoll410:
Thank you sooo much 4 selecting my answer as a brainliest one(^^)
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