Mathematics for IGCSE & O level - Coordinate Geometry (Section 4 - No. 28)
What is the equation of the line that passes through (1, 1) and has a gradient of 2?
y = x + 1
y = 2x - 1
y = 2x + 1
y = x - 1
คำอธิบาย
Use the point-slope form y - y1 = m(x - x1) => y - 1 = 2(x - 1) => y = 2x - 1