After reading the directions to paint, on the paint drum, the information indicated two coats of paints is required when using the 5 liter paint and one coat with the 20 liter drum. With both paints 1 litre of paint covers 9 meter squared. There are 28 rooms to be painted. Show with calculations which will be cheaper paint to buy​

29 rooms left to uncover the paint from the 9 meter squared rooms

Abit confused about what you mean, but i think you might be referring to slope intercept form: y = mx + bin that case b, or the y intercept is already given.(0,-1)find the slope by using the formulay2 - y1/x2 - x1the final slope will be 4/2, equivalent to 2.now your equation should look like thisy = 4/2x -1sorry if this didn’t you out!