if p=2x is even, then p^2 is also even

[math_celebrity]

if p=2x is even, then p^2 is also even

p^2 = 2 * 2 * x^2
p^2 = 4x^2

This is true because:

• If x is even, then x^2 is even since two evens multiplied by each other is even and 4x^2 is even
• If x is odd, the x^2 is odd, but 4 times the odd number is always even since even times odd is even