If x + y ∝ x – y, let us show that

ax + by ∝ px + qy

[where a, b, p, q are non zero constant]

6

If x + y ∝ x – y, let us show that

x² + y²∝ xy

6

If x + y ∝ x – y, let us show that

x³ + y³∝ x³ – y³

7

If a² + b²∝ ab, let us prove that a + b ∝ a – b.

7

If x³ + y³∝ x³ – y³, let us prove that x + y ∝ x – y.