Question

Answer 1

b. Ta có:  (x-2)(x²+2x+4) - x(x²-1) = 3x-4

<=> (x³-8) - (x³-x) = 3x-4

<=> x³- 8 - x³ + x = 3x-4

<=> x-8-3x+4 = 0

<=> -4-2x = 0

<=> x=2

      Vậy, x=2

Answer 2

Lời giải:

PT $\Leftrightarrow (x^3-2^3)-(x^3+x)=3x-4$

$\Leftrightarrow x^3-8-x^3-x=3x-4$

$\Leftrightarrow -8-x=3x-4$

$\Leftrightarrow 4x+4=0$

$\Leftrightarrow x=-1$