The answer is -6/7 or -0.857142
Answer:
251
Step-by-step explanation:
Hello :
the nth term ( general term of an arithmetic sequence is :
An =A1+(n-1)d ....a common difference is : d , A1 : the first terme
A1 = 5 and : d = 1 - 5 = - 4 n = 21
A21 = 5 + (21 -1)(-4)
A21 = 5 - 80 = -75
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