Answer:
x=-16
Step-by-step explanation:
Subtract 4 from both sides
x+4-4=-12-4
x=-16
If
is the first number in the progression, and
is the common ratio between consecutive terms, then the first four terms in the progression are

We want to have

In the second equation, we have

and in the first, we have

Substituting this into the second equation, we find

So now we have

Then the four numbers are

Answer:
The 13th term is 81<em>x</em> + 59.
Step-by-step explanation:
We are given the arithmetic sequence:

And we want to find the 13th term.
Recall that for an arithmetic sequence, each subsequent term only differ by a common difference <em>d</em>. In other words:

Find the common difference by subtracting the first term from the second:

Distribute:

Combine like terms. Hence:

The common difference is (7<em>x</em> + 5).
To find the 13th term, we can write a direct formula. The direct formula for an arithmetic sequence has the form:

Where <em>a</em> is the initial term and <em>d</em> is the common difference.
The initial term is (-3<em>x</em> - 1) and the common difference is (7<em>x</em> + 5). Hence:

To find the 13th term, let <em>n</em> = 13. Hence:

Simplify:

The 13th term is 81<em>x</em> + 59.
Hi there! The slope of the line is -2/5.
We can determine the slope of a line by dividing the change of y-coordinates by the change of x-coordinates.
In this situation we have a...
change of x-coordinates of (5 - 0) = 5
change of y-coordinates of (0 - 2) = -2
Therefore, the slope of this line is -2/5