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RoLexx
What is the 25th term of the arithmetic sequence where a1 = 8 and a9 = 48 ?
a1 = 8 a2 = a1 + d a3 = (a1 + d) + d a4 = ((a1+d)+d)+d = a1 + 3d an = a1 + d(n-1)
a9 = 48 = 8 + d(7) to solve for d
i got lost; 48 = 8 + d(8) :)
looks like d=5 in this case a25 = a1 + d(24) a25 = 8 + 5(24)