You can put this solution on YOUR website!
The gradient is equal to the change in y divided by the change in x.
There is no change in x between the two ponts, so the gradient is equal to the change in y divided by zero.
Anything divided by zero is equal to infinity.
Therefore the slope of the line is equal to plus or minus infinity (it is impossible to tell if the line goes straight "up" or "down")!
I hope this helps.
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