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the slope = m (y2-y1)/ (x2-x1)
using two points for example (2, 1) and (0, -3)
m = (y2-y1)/ (x2-x1)
m = ( -3 -1 )/(0-2) = -4/ -2 = 2
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From the graph (in green )
m= variation in y / variation in x= 4/ 2 = 2
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Answer
The slope is 2
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hint