Given a and b are two rational numbers, fulfilling the equality

** a^3 + 4a^2*b = 4a^ 2 + b^4.**
Prove that the value of
** sqrt(a-1)** is a rational number.

att:solvers

...Prove that the value of* *** sqrt(a-1)** is a rational number

was **sqrt(a)-1 **in the original text, not **sqrt(a-1)**

Clearly if *sqrt(a)-1=m/n *

** then ** *sqrt(a)=1+m/n= (m+n)/n , *__a rational number__

Brian has actually discovered the error and solved __ __assuming

"Prove that the value of* ***sqrt(a)** is a rational number" __ __