Question 877410
The steps shown do not match the given data to any extent.  Start with the correct values in the slope formula  (and you mentioned "gradient" which is probably something else):


{{{(2-x)/(0-1)=4}}};
and do your steps from it.


REMARK:
You wanted help and then found or claimed it to be useless; but on the contrary, the help is plainly on target.  Your question as posted differs from the steps you showed.  You did not properly follow the slope formula, while I in fact used it for you directly.