All you need to know is that a km is 1000 m ( as the prefix kilo always means 1000 let it be even 1kg and that is equal to 1000g )
also know
that a 100 cm is 1 m and that's cause the prefix centi is 10^–2 (0.01) 
answering your question 
a) 5km = 5000m 
 5km and 20m in m is 5000m + 20m = 5020m
b) 13 cm = 13/100m = 0.13m
 7m and 12cm is 7m + 0.13m = 7.13m.
remember 
1km = 1000m
100cm = 1m
<em>hope</em><em> </em><em>this</em><em> </em><em>helped</em><em> </em>:)
 
        
             
        
        
        
First we need to find the slope.
slope = (y2 - y1) / (x2 - x1)
slope = (-5 - 2) / (5 - -3)
slope = (-7) / (5 + 3)
slope = -7/8
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Point-slope form:
y - y1 = m(x - x1)
y - 2 = (-7/8)(x - -3)
y - 2 = (-7/8)(x + 3)
y - 2 = (-7/8)x - 21/8
y = (-7/8)x - 21/8 + 2
y = (-7/8)x - 21/8 + 16/8
y = (-7/8)x - 5/8
        
                    
             
        
        
        
Answer:14
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
option A. y = 1/2 x 
Step-by-step explanation:
given the equation:
y - 9 = 1/2 ( x - 3 )
here the gradient is 1/2
if passes parallel the gradient is same.
the line pass through ( -2 , -1 )
so,
y - y1 = m( x -  x1 )
y - - 1 = 1/2 ( x - -2 )
y + 1 = x/2 + 1
y = 1/2 x 
Therefore option A is correct.