Question

a/ (x² +2x)² - (3x+2)²=0

b/ (x+2)² - 3|x+2| - 4=0

c/ (x-1)(x²-3x-4)

Answer 1

a: \(\left(x^2+2x\right)^2-\left(3x+2\right)^2=0\)

\(\Leftrightarrow\left(x^2+2x-3x-2\right)\left(x^2+2x+3x+2\right)=0\)

\(\Leftrightarrow\left(x^2-x-2\right)\left(x^2+5x+2\right)=0\)

hay \(x\in\left\{2;-1;\dfrac{-5+\sqrt{17}}{2};\dfrac{-5-\sqrt{17}}{2}\right\}\)

b: \(\left(x+2\right)^2-3\left|x+2\right|-4=0\)

\(\Leftrightarrow\left(\left|x+2\right|\right)^2-3\left|x+2\right|-4=0\)

\(\Leftrightarrow\left|x+2\right|-4=0\)

=>x+2=4 hoặc x+2=-4

=>x=2 hoặc x=-6