Mathematics for IGCSE & O level - Coordinate Geometry (Section 3 - No. 31)
What is the equation of a line with gradient -1 that passes through the point (3, -2)?
y = -x + 1
y = -x - 5
y = x - 5
y = x + 1
คำอธิบาย
Using point-slope form, y - (-2) = -1(x - 3) => y + 2 = -x + 3 => y = -x + 1