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In an arithmetic sequence the first term is {a} and the second term is {b}.

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The common difference is the difference between any two consecutive terms. In this case the first and second term. 

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common difference = $\\var{b} - \\var{a} = \\var{d}$

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To find any term in a sequence use the formula $u_n = u_1 + (n-1)d$

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In this case $u_8 = \\var{a} + 7 \\times \\var{d} = \\var{a + 7d}$

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first term

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common difference (restricted to small integers)

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second term based on common difference.

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Find the common difference.

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Find the eighth term.

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