Mathematics for IGCSE & O level - Proportion (Section 1 - No. 1)
Which of the following represents the correct equation if *y* is directly proportional to *x*?
y = kx
x = ky
x*y=k
x/y=k
คำอธิบาย
When *y* is directly proportional to *x*, then y = kx or x = ky or x/y=k where k is a constant