in an ap the first term is 25 , nth term is -17 and the sum of first n terms is 60, find a and d
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Sn=n/2(1st term + nth term)
60×2 = n(25-17)
120=8n
n= 120/8
n= 15
therefore, t15 = - 17 and a = 25
t15 = a+ 14d
-17 = 25 + 14d
-17-25=14d
d= -42/14
d = -3
Therefore, a= 25
d= -3
hope this helps you.
don't forget to do it brainleist.
60×2 = n(25-17)
120=8n
n= 120/8
n= 15
therefore, t15 = - 17 and a = 25
t15 = a+ 14d
-17 = 25 + 14d
-17-25=14d
d= -42/14
d = -3
Therefore, a= 25
d= -3
hope this helps you.
don't forget to do it brainleist.
chhajedchirag1p32bb2:
please do it brainleist.
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