Question

Tìm x, biết:

a) x³-\(\frac{1}{9}\)x=0

b) x(x-3)+x-3=0

c) x²(x-3)+27-9x=0

Answer 1

b) \(x^2-2x-3=0\)

\(D=b^2-4ac\)

\(\left(-2\right)^2-\left(4\left(1.3\right)\right)=16\)

\(x_{1,2}=\frac{-b-\sqrt{D}}{2a}=\frac{2-\sqrt{16}}{2}\)

\(x=1;-3\)

Answer 2

a)1/3
b)-1
c)3

Answer 3

\(\frac{x^3\left(-1\right)}{9}=-\frac{x^3}{9}\)

\(-\frac{x^3}{9}=0\Rightarrow x=0\)