Question

A5=86 a17=104a1=?d=? ​

Answer 1

1) Формула для определения любого члена арифметической прогрессии:

aₓ = a₁ + d*(х−1)

2) Тогда формулы для определения пятого и семнадцатого членов прогрессии:

а₅ = а₁ + d*(5-1) = a₁ + 4d

a₁₇ = a₁ + d*(17-1) = a₁ + 16d

3) Подставим вместо а₅ и а₁₇ их значения и получим систему уравнений:

86 = а₁ + 4d

104 = а₁ + 16d

Из второго уравнения вычтем первое:

18 = 16d - 4d

18 = 12d

d = 1,5

4) Подставим значение d = 1,5 в одно из уравнений, например в первое:

86 = а₁ + 1,5*4

86 = а₁ + 6

а₁ = 80

Ответ: а₁ = 80; d = 1,5

Answer 2

It seems like there is a pattern in the given equations. Let's try to decipher it:

A5 = 86: Here, the letter 'A' followed by a number 5 results in the number 86.

A17 = 104: Similarly, the letter 'A' followed by a number 17 results in the number 104.

Now, we need to find the value of 'a1' and 'd.'

From the pattern, we can see that the number increases by 18 each time we increase the number following 'A.' Therefore:

A1 = A5 - 18 = 86 - 18 = 68

Now, let's determine the common difference 'd':

d = (A17 - A5) / (17 - 5) = (104 - 86) / 12 = 18 / 12 = 1.5

So, the values we were looking for are:

a1 = 68 d = 1.5

If you meant something else by the given equations, please provide more context or clarify the pattern you intended, and I'll be happy to assist further.