Answer:
Slope = -2
Y intercept = 4
Equation. y = -2x +5
Step-by-step explanation:
Using points, (1,2) and (3,-2)
Slope = (-2-2)/(3-1) = -4/2 = -2
Y intercept = 4
-2 = (y-3)/(x-1)
-2(x-1) = y-3
-2x +2 = y-3
y = -2x +2 +3 
y = -2x +5
 
        
                    
             
        
        
        
-4r-11=4r+21
Move 4r to the other side
Sign changes from +4r to -4r
-4r-4r-11=4r-4r+21
-4r-4r-11=21
-8r-11=21
Move -11 to the other side
Sign changes from -11 to +11
-8r-11+11=21+11
-8r=21+11
-8r=32
Divide both sides by -8
-8r/-8=32/-8
Answer: r=-4