Answer:
The first term is 12. The common difference is 4.
Step-by-step explanation:
[tex] a_n = a_1 + d(n - 1) [/tex]
The difference between the third and seventh terms is
36 - 20 = 16
The 7th term is the 4th term after the 3rd term, so the common difference is
16/4 = 4
[tex] a_3 = a_1 + 4(3 - 1) [/tex]
[tex] 20 = a_1 + 4(3 - 1) [/tex]
[tex] 20 = a_1 + 8 [/tex]
[tex] a_1 = 12 [/tex]
Answer: The first term is 12. The common difference is 4.
