Question

Tìm a ; b nguyên khác 0 thỏa mãn: a+b=ab

Answer 1

a + b = ab

=> ab - a - b = 0

=> a(b - 1) - (b - 1) = -1

=> (a - 1)(b - 1) = -1

...

Answer 2

\(x = {-b \pm \sqrt{b^2-4ac} \over 2a}\)