Question

 

Tìm a,b biết

a+b=ab=a:b

 

Answer 1

a+b=a.b \(\Rightarrow\)a=a.b-b=b(a-1)

Thay a=b-1 vào a+b=a:b, ta có:

\(a+b=\frac{b\left(a-1\right)}{b}=a-1\)

\(\Rightarrow a+b=a-1\Rightarrow a+b-a=-1\Rightarrow b=-1\)

Ta có

\(a.b=a+b\Leftrightarrow-1.a=a+\left(-1\right)\Rightarrow-a=a-1\Rightarrow-2a=-1\Rightarrow a=\frac{1}{2}\)

Vậy \(a=\frac{1}{2};b=-1\)