given an= 4 d= 2 sn= -14 find n and
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Step-by-step explanation:
an=a+(n-1)d
4=a+(n-1)2
4=a+2n-2
6=a+2n......(1)
Sn=n/2[2a + (n-1)d]
-14=n/2[2(2n-6)+(n-1)2]...by eq(1)
-14=n/2[4n-12+2n-2]
-14=n[2n-6+n-1]
-14=n[3n-7]
-14=3n^2-7n
=3n^2-7n+14
By solving this,you will get n
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