Example 4 Two terms of an arithmetic sequence are a8 = 21 and a27 = 97. Find a rule for the nth term.
{"Image DocumentName": "Example 4Two terms of an arithmetic sequence are a8 = 21 and a27 = 97. Find a rule for the nth term.", "Image ImageDescription": "SOLUTION. STEP 1. Write a system of equations using an = a1 + (n \u2013 1)d and substituting 27 for n (Equation 1) and then 8 for n (Equation 2).", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}