A2-a8=-60 a3 + a7 =- 40 A1=? D=?

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вопрос

To find the values of A1 and D, we need to use the given equations and solve for A1 and D.

Given:

A2 - A8 = -60
A3 + A7 = -40

To find A1, we will start with the formula for an arithmetic sequence:
An = A1 + (n-1)d

Since A2 - A8 = -60, we can rewrite the equation as:
A1 + d - A1 - 7d = -60
-6d = -60
d = 10

Now that we have found the common difference (d = 10), we can use the second equation to find A1:
A3 + A7 = -40
A1 + 2d + A1 + 6d = -40
2A1 + 8d = -40
2A1 + 80 = -40
2A1 = -120
A1 = -60

Therefore, the value of A1 is -60 and the common difference, D, is 10.