Number 7:   11/12-9/10 = 110/120-108/120=2/120= 1/60
number 8:     5/18-1/3=15/54-5/54=10/54 =5/27
        
                    
             
        
        
        
Answer:
3x + 2
Step-by-step explanation:
 
        
             
        
        
        
Let w represent the width of the rectangle in cm. Then its length in cm is (3w+9). The perimeter is the sum of two lengths and two widths, so is ...
... 418 = 2(w + (3w+9))
... 209 = 4w +9 . . . . . . divide by 2, collect terms
... 200 = 4w . . . . . . . . subtract 9
... 50 = w . . . . . . . . . . divide by 4
... length = 3w+9 = 3·50 +9 = 159
The dimensions of this piece of land are 159 cm by 50 cm.