Đáp án:
Giải thích các bước giải:
a) $3x - 5x(x - 1001) = 3003$
$3x - 5x² + 5005x = 3003$
$3x - 5x² + 5005x - 3003 = 0$
$5x² - 3x - 5005x + 3003 = 0$
$x(5x - 3) - 1001(5x - 3) = 0$
$(5x - 3)(x-1001) = 0$
\(\left[ \begin{array}{l}x=\dfrac{3}{5}\\x=1001\end{array} \right.\)
b)$ (x + 2) (x − 1) − x + 1 = 0$
$x² + x - 2 - x + 1 = 0$
$x² - 1 = 0$
$(x-1)(x+1) = 0$
\(\left[ \begin{array}{l}x=1\\x=-1\end{array} \right.\)
c)
$(x² - 11)(7-2x) - 4x = -14$
$7x² - 2x³ - 77 + 22x - 4x + 14 = 0$
$7x² - 2x³ + 18x - 63 = 0$
$2x³ - 7x² - 18x + 63 = 0$
$2x³ + 6x² - 13x² - 39x + 21x + 63 = 0$
$(2x² - 13x + 21)(x+3) = 0$
$(2x² - 6x - 7x + 21)(x+3) = 0$
$(2x - 7)(x-3)(x+3) = 0$
$\begin{cases} x = \dfrac{7}{2}\\x = 3\\x = -3 \end{cases}$
