I am puzzled by this! Where did you get this question? If it was for a class, surely you were given the
definition of "gradient of a line" first?
And if you just ran across the term on the internet couldn't you have "googled" "gradient of a line"?
When I did that, I got 4,690,000 hits, the first of which was
https://www.mathsisfun.com/gradient.htm ... 0line%20is.
which gives the formula: [tex]\frac{y_1- y_0}{x_1- x_0}[/tex].