Answer:
[tex]r=4[/tex]
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:
[tex]y-y_1=m(x-x_1)[/tex]
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:
[tex]y-(3)=-1(x-(-9))[/tex]
Simplify:
[tex]y-3=-(x+9)[/tex]
Distribute:
[tex]y-3=-x-9[/tex]
Add 3 to both sides. So, our equation is:
[tex]y=-x-6[/tex]
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:
[tex]r=-(-10)-6[/tex]
Evaluate for r. Distribute:
[tex]r=10-6[/tex]
Subtract:
[tex]r=4[/tex]
So, the value of r is 4.
And we're done!
