Question
The third term of an arithmetic sequence is -12 and the seventh term is 8.what is the sum of the first 10 terms?
Answers
Reiny
Use your definitions and formulas
a + 2d = -12
a + 6d = 8
subtract the two equations, and find d
once you have d, go back into the first equation to find a
then find a + 9d
a + 2d = -12
a + 6d = 8
subtract the two equations, and find d
once you have d, go back into the first equation to find a
then find a + 9d