Working out the intercept of the Y axis?

Question

If a gradient of -578.947 is present on a line of best fit then how can you work out the intercept of the Y-Axis when a co-ord of:

(0.00110,0.0000019) is given?

Thank you

Answer 1

let (0,y) be the y-intercept. slope (gradient) is change in y (dy) over change in x (dx), so solve
(y - 0.0000019)/(0 - 0.00110) = -578.947
y - 0.0000019 = 0.6368417
y = 0.6368436