Question

tìm x

a/ x(x-2009)-2010x+2009.2010=10

b/ 4x²-25=0

c/ x³-4x²+4x=0

thank trước nha

Answer 1

b, \(4x^2-25=0\)

\(\Leftrightarrow4x^2=25\)

\(\Leftrightarrow x^2=\frac{25}{4}=\left(\pm\frac{5}{2}\right)^2\)

\(\Leftrightarrow x=\pm\frac{5}{2}\)

     Vậy \(x\in\left\{\frac{5}{2};-\frac{5}{2}\right\}\)

Answer 2

c) x³ - 4x² + 4x = 0

=> x³ - 2x² - 2x² + 4x = 0

=> x².(x - 2) - 2x.(x - 2) = 0

=> (x - 2).(x² - 2x) = 0

=> (x - 2).x.(x - 2) = 0

=> (x - 2)².x = 0

=> (x - 2)² = 0 hoặc x = 0

=> x - 2 = 0 hoặc x = 0

=> x = 2 hoặc x = 0