Answer:
Step-by-step explanation:
We know that the slope of the line is -1.
We also know that the line passes through (-9, 3) and (-10, r).
We want to find the value of r.
First, let's figure out the equation of our line. We can use the point-slope form:
Where m is the slope and (x₁, y₁) is a point.
So, let's substitute -1 for m. Since we know the point (-9, 3), let's use this for (x₁, y₁).
Substitute:
Simplify:
Distribute:
Add 3 to both sides. So, our equation is:
It passes through (-10, r) and we want to find the value of r. So, let's substitute -10 for x and r for y, since -10 is our x and r is our y. So:
Evaluate for r. Distribute:
Subtract:
So, the value of r is 4.
And we're done!