Question

Giúp mình với nhanh nhanh nhé, cảm ơn a) ( x^2 + x )^2 + 2( x^2 + x ) - 8 = 0 b) ( x^2 - 4x +3 ) ( x^2 +6x + 8 ) + 24 = 0 c) 6x^4 + 25x^3 + 12x^2 - 25x + 6 = 0 d) ( x - 2 )^4 + ( x- 3 )^4 = 0

Answer 1

a: \(\left(x^2+x\right)^2+2\left(x^2+x\right)-8=0\)

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

\(\Leftrightarrow\left(x+2\right)\left(x-1\right)=0\)

hay \(x\in\left\{-2;1\right\}\)

b: \(\Leftrightarrow\left(x-1\right)\left(x-3\right)\left(x+2\right)\left(x+4\right)+24=0\)

\(\Leftrightarrow\left(x^2+x-2\right)\left(x^2+x-12\right)+24=0\)

\(\Leftrightarrow\left(x^2+x\right)^2-14\left(x^2+x\right)+48=0\)

\(\Leftrightarrow\left(x^2+x-6\right)\left(x^2+x-8\right)=0\)

hay \(x\in\left\{-3;2;\dfrac{-1+\sqrt{33}}{2};\dfrac{-1-\sqrt{33}}{2}\right\}\)