In slope-point form a line with slope m through point (X, Y) has equation: y - Y = m(x - X) → y = mx + Y - mX → y = mx + c where: m is the slope c = Y - mx is the intercept → The line with slope 2 through the point (1, 1) has equation: y = 2x + 1 - 2×1 → y = 2x - 1