The equation of a line in slope-intercept form is
y = mx + b
where m represents the slope and b, the y-intercept.
here we have m = 2 and so the partial equation is
y = 2x + b
To find the value of b, substitute the coordinates of the point (1 ,1) into the partial equation That is x = 1 and y = 1.
-> (2 x 1) + b = 1 -> 2 + b = 1 -> b = -1
-> y = 2x - 1 is equation in slope-intercept form