Answer:

Explanation:
We have the two points: (2, -3) and (k, 7).
And we want to find the value of k such that the slope between these two points is -1.
So, we can use the slope formula:

Let (2, -3) be (x₁, y₁) and let (k, 7) be (x₂, y₂). Let's also substitute the slope m for -1. This gives us:

So, let's solve for k. Add in the numerator:

Notice that we can rewrite the left side as:

Now, we can cross-multiply:

Divide both sides by -1. This removes the negative on the left:

Finally, add 2 to both sides. So, the value of k is:

And we're done!