(8,1)(8,-4)
notice how the x values are the same.....this means that the line is a vertical line which has an undefined slope.
This helps :
VUX -- vertical line, undefined slope, represented by x = a number (if both values of x are the same)
HOY -- horizontal line, 0 slope, represented by y = a number (if both values of y are the same)
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rise of 3 and a run of 12....slope = rise / run...so ur slope is 3/12 which reduces to 1/4
