Squaring both sides of the given equation:  w^2=7w, or w^2-7w=0.  
w^2-7w=0 can be factored:  w(w-7)=0.  Then, w=7 or w=0.  Both 0 and 7 are solutions of this equation.
        
             
        
        
        
What you need to do is give these problems a common denominator. Which makes 3/21 and14/21 respectively. Logically, you need to walk 4/21 of the trail. This can’t be simplified further.
        
             
        
        
        
Start by factoring an x term out of the equation:
x(x-11)=0
Now, you can set each term equal to zero and solve for x:
x=0
x-11=0
x=11
x={0, 11}
Hope this helps!!