∴4a？ +8ab+4b？ ≤2a？ +2b？
∴2a？ +8ab+2b？ ≤0
∴a？ +4ab+b？ ≤0
Divide both sides by b at the same time? , get
(a/b)? +4(a/b)+ 1≤0
∴(-a/b)？ -4(-a/b)+ 1≤0
Take -a/b as the unknown,
Solve the unary quadratic inequality and get:
2-√3≤-a/b≤2+√3