Làm hộ mik bài 4, 5 zớii :<

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Làm hộ mik bài 4, 5 zớii :<

Question

Làm hộ mik bài 4, 5 zớii :<
lam-ho-mik-bai-4-5-zoii

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Môn Toán Khoii Minh 4 years 2020-10-14T04:52:33+00:00 2020-10-14T04:52:33+00:00 1 Answers 87 views 0

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Captcha* Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )

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Gerda · Answer 1 · 2020-10-14T04:53:41+00:00

$B à i 4_{}$

$a) x^{2} - 4 = 0_{}$

$\Leftrightarrow (x - 2) (x + 2) = 0_{}$

$\Leftrightarrow x = \pm 2_{}$

$b)_{}$ $x^{2} + 10 x + 16 = 0_{}$

$\Leftrightarrow x^{2} + 8 x + 2 x + 16 = 0_{}$

$\Leftrightarrow x . (x + 8) + 2 (x + 8)_{}$

$\Leftrightarrow (x + 8) . (x + 2) = 0_{}$

$\Leftrightarrow_{}$ $[\begin{array}{l} x + 8 = 0 \\ x + 2 = 0 \end{array}$ $\Leftrightarrow_{}$ $[\begin{array}{l} x = - 8 \\ x = - 2 \end{array}$

$c)_{}$ $(x^{2} + 2 x)^{2} - x^{2} - 2 x - 2 = 0_{}$

$\Leftrightarrow x^{4} + 4 x^{3} + 4 x^{2} - x^{2} - 2 x - 2 = 0_{}$

$\Leftrightarrow x^{4} + x^{3} + 3 x^{3} + 3 x^{2} - 2 x - 2 = 0_{}$

$\Leftrightarrow x^{3} (x + 1) + 3 x^{2} (x + 1) - 2 (x = 1) = 0_{}$

$\Leftrightarrow (x + 1) (x^{3} + 3 x^{2} - 2) = 0_{}$

$\Leftrightarrow (x + 1) (x^{3} + x^{2} + 2 x^{2} - 2 + 2 x - 2 x) = 0_{}$

$\Leftrightarrow (x + 1) [x^{2} (x + 1) + 2 x (x + 1) - 2 (x + 1)] = 0_{}$

$\Leftrightarrow (x + 1) (x + 1) (x^{2} + 2 x - 2) = 0_{}$

$\Leftrightarrow (x + 1)^{2} . (x^{2} + 2 x - 2) = 0_{}$

$\Leftrightarrow_{}$ $[\begin{array}{l} (x + 1)^{2} = 0 \\ x^{2} + 2 x - 2 = 0 \end{array}$ $\Leftrightarrow_{}$ $[\begin{array}{l} x = - 1 \\ x = - 1 \pm \sqrt{3} \end{array}$

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