Seems like I've done a few of these already today.
1.
a[1] = 4, d=6
Formula: a[n] = 4 + 6(n-1)
a[40]=4 + 6(39) = 238
Table: 4 10 16 22 28 34 ... a[40]=238
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2.
a[23]=25, d=3
a[n] = a[1] + d(n-1)
25=a[23]=a[1] + 3(22)
a[1] = 25 - 66 = -41
Table: -41 -38 -35 -32 -29 -26
Let's check a[23]= -41 + 3(22)= 25, good
Formula: a[n] = -41 + 3(n-1)
