Suppose that :
A = ( 0 , - 15 )
&
B = ( 11 , - 4 )
Slope = m = [ y(A) - y(B) ] ÷ [ x(A) - x(B) ]
Now let's juts put the coordinates in the formula to find the slope :
Slope = m = [ - 15 - ( - 4 ) ] ÷ [ 0 - 11 ]
Slope = m = [ - 15 + 4 ] ÷ [ - 11 ]
Slope = m = - 11 ÷ ( - 11 )
Slope = m = 1
