Question

I just need a explanation for this.

Answer 1

C

Explanation:

thisTo find the explicit form of this sequence, you have to use this formula.

`A_n=a_1+d(n-1)`, when d is a common difference, and a1 is the first term.

So for this problem, you first have to find the common difference; you can do this by looking at how much is added or subtracted from one of the numbers to get the next term. In this case, the common difference is -9.

The a1 is the first term or -1.

So to get the explicit formula for this, you need to insert these values into the equation.

`A_n=a_1+d(n-1)\\\\A_n=-1+-9(n-1)`

So to get it in the form of the other answers or the problem, you need to distribute the -9 and combine any like terms.

This is done as shown:

`A_n=-1+-9(n-1)\\\\A_n=-1+-9n+9\\\\A_n=-9n+9-1\\\\A_n=-9n+8`

So this is how they got the answer of C.