3X(X - 5) - X2 + 25 = 03X(X - 5) - (X2 + 25) = 03X(X - 5) - (X +...

Bài 3.3x(x - 5) - x

²

+ 25 = 03x(x - 5) - (x

²

+ 25) = 03x(x - 5) - (x + 5)(x - 5) = 0(3x - x - 5)(x - 5) = 0(2x - 5)(x - 5) = 0