SOLUTION: If the 4th term of an arithmetic sequence is 24 and the 12th term is 56, what is the first term??

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Question 1088826: If the 4th term of an arithmetic sequence is 24 and the 12th term is 56, what is the first term??
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
a, first term
d, common difference

system%28a%2B3d=24%2Ca%2B11d=56%29
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11d-3d=56-24
8d=32
d=4

a=24-3d
a=24-3%2A4
a=24-12
highlight%28a=12%29