Question

tìm x (x+2)(x^2-2x+4)-(x(x+3)(x-3)=26

Answer 1

\(\Leftrightarrow\left(x+2\right)\left(x^2-2x+2^2\right)-x\left(x^2-3^2\right)=26\\ \Leftrightarrow x^3+2^3-x^3+9x=26\\ \Leftrightarrow9x+8=26\\ \Rightarrow x=\dfrac{26-8}{9}=2\)

Answer 2

Lời giải:

$(x+2)(x^2-2x+4)-x(x+3)(x-3)=26$

$\Leftrightarrow x^3+8-x(x^2-9)=26$

$\Leftrightarrow 9x+8=26$

$\Leftrightarrow 9x=18$

$\Leftrightarrow x=2$