Question

Show that the sequence defined by an:5n - 7 is an AP
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Answer 1

Answer:

put n=1 in 5n-7=5*1-7=-2

put n=2in 5n-7=5*2-7=3

put n=3 in 5n-7=5*3-7=8

now d=3-(-2)=5

d=8-3=5

since difference are equal

therefore it is a p