Help Solving Calc. Equations: a3-6a=b3-6b & a4-4a2=b4-4b2

[dorian_gray]

personally i do not know the details of these equations itself, but my friend seems to be having some trouble solving this question in a calc. textbook, let's see if you guys can shed some light on the question

Homework Statement

a³-6a=b³-6b
a⁴-4a²=b⁴-4b²
solve for a

Homework Equations

umm personally I am not sure?

The Attempt at a Solution

no attempt can be written here, but apparently the answer is a²=6

 

[╔(σ_σ)╝]

There is missing information.

Seriously, the only thing I can conclude from the equations is that a=b.