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If the common difference in an arithmetic sequence is 4, and the 20th term is 36, what is the first term?A.-40 B. 76 C. 40 D. 2​

Respuesta :

unicorn3125

Answer:

             A.  - 40

Step-by-step explanation:

[tex]a_n=a_1+d(n-1)\\\\a_{20}=a_1+d(20-1)\\\\36=a_1+4\cdot19\\\\36=a_1+76\\\\a_1=36-76\\\\a_1=-40[/tex]

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