Question

D=3. An=a1+(n-1)×d A5=15 A1=?

Answer 1

Ответ:

Пошаговое объяснение:

a₅ = a₁ + 4*3 = 15 ⇒  a₁ = 15 -12 = 3

Answer 2

In the given arithmetic sequence, we have the common difference $d = 3$, and we're given that $A_5 = 15$.

The formula for the $n$th term of an arithmetic sequence is given by $A_n = A_1 + (n - 1) \times d$, where $A_1$ is the first term and $d$ is the common difference.

We can rearrange this formula to solve for $A_1$:

$A_5 = A_1 + (5 - 1) \times 3$ $15 = A_1 + 12$

Now, let's isolate $A_1$:

$A_1 = 15 - 12$ $A_1 = 3$

So, the first term ($A_1$) in the arithmetic sequence is 3.