What is the constant of proportionality in the equation y=2.5 times x? this is a khan academy question.

Use mathematical induction to prove the statement is true for all positive integers n, or show why it is false. 1^2 + 4^2 + 7^2 + + (3n - 2)^2 = [n(6n^2-3n-1)/2]

If a and b are real numbers, then |a-b| is always, sometimes or never equal to |b-a| ?

Use the real number line shown below to complete the statement