mng giúp em vs ……………………………………………. Question mng giúp em vs ……………………………………………. in progress 0 Môn Toán Vodka 4 years 2020-10-29T14:50:55+00:00 2020-10-29T14:50:55+00:00 1 Answers 72 views 0
Answers ( )
Giải thích các bước giải:
Ta có:
\(\begin{array}{l}
a,\\
4x\left( {x + 1} \right) = 8.\left( {x + 1} \right)\\
\Leftrightarrow 4x.\left( {x + 1} \right) – 8.\left( {x + 1} \right) = 0\\
\Leftrightarrow \left( {x + 1} \right).\left( {4x – 8} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
x + 1 = 0\\
4x – 8 = 0
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = – 1\\
x = 2
\end{array} \right.\\
b,\\
x\left( {x – 1} \right) – 2\left( {1 – x} \right) = 0\\
\Leftrightarrow x\left( {x – 1} \right) + 2.\left( {x – 1} \right) = 0\\
\Leftrightarrow \left( {x – 1} \right)\left( {x + 2} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
x – 1 = 0\\
x + 2 = 0
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = 1\\
x = – 2
\end{array} \right.\\
c,\\
2x\left( {x – 2} \right) – {\left( {2 – x} \right)^2} = 0\\
\Leftrightarrow 2x\left( {x – 2} \right) – {\left( {x – 2} \right)^2} = 0\\
\Leftrightarrow \left( {x – 2} \right).\left[ {2x – \left( {x – 2} \right)} \right] = 0\\
\Leftrightarrow \left( {x – 2} \right)\left( {x + 2} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
x – 2 = 0\\
x + 2 = 0
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = 2\\
x = – 2
\end{array} \right.\\
d,\\
{\left( {x – 3} \right)^3} + 3 – x = 0\\
\Leftrightarrow {\left( {x – 3} \right)^3} – \left( {x – 3} \right) = 0\\
\Leftrightarrow \left( {x – 3} \right).\left[ {{{\left( {x – 3} \right)}^2} – 1} \right] = 0\\
\Leftrightarrow \left[ \begin{array}{l}
x – 3 = 0\\
{\left( {x – 3} \right)^2} – 1 = 0
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x – 3 = 0\\
x – 3 = 1\\
x – 3 = – 1
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = 3\\
x = 4\\
x = 2
\end{array} \right.\\
e,\\
5x.\left( {x – 2} \right) – \left( {2 – x} \right) = 0\\
\Leftrightarrow 5x.\left( {x – 2} \right) + \left( {x – 2} \right) = 0\\
\Leftrightarrow \left( {x – 2} \right).\left( {5x + 1} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
x – 2 = 0\\
5x + 1 = 0
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = 2\\
x = – \frac{1}{5}
\end{array} \right.\\
g,\\
5x\left( {x – 2000} \right) – x + 2000 = 0\\
\Leftrightarrow 5x\left( {x – 2000} \right) – \left( {x – 2000} \right) = 0\\
\Leftrightarrow \left( {x – 2000} \right)\left( {5x – 1} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
x – 2000 = 0\\
5x – 1 = 0
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = 2000\\
x = \frac{1}{5}
\end{array} \right.\\
h,\\
{x^2} – 4x = 0\\
\Leftrightarrow x.\left( {x – 4} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
x = 0\\
x – 4 = 0
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = 0\\
x = 4
\end{array} \right.\\
k,\\
{\left( {1 – x} \right)^2} – 1 + x = 0\\
\Leftrightarrow {\left( {1 – x} \right)^2} – \left( {1 – x} \right) = 0\\
\Leftrightarrow \left( {1 – x} \right).\left[ {\left( {1 – x} \right) – 1} \right] = 0\\
\Leftrightarrow \left( {1 – x} \right).\left( { – x} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
1 – x = 0\\
– x = 0
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = 0\\
x = 1
\end{array} \right.\\
m,\\
x + 6{x^2} = 0\\
\Leftrightarrow x.\left( {1 + 6x} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
x = 0\\
1 + 6x = 0
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = 0\\
x = – \frac{1}{6}
\end{array} \right.\\
n,\\
\left( {x + 1} \right) = {\left( {x + 1} \right)^2}\\
\Leftrightarrow \left( {x + 1} \right) – {\left( {x + 1} \right)^2} = 0\\
\Leftrightarrow \left( {x + 1} \right).\left[ {1 – \left( {x + 1} \right)} \right] = 0\\
\Leftrightarrow \left( {x + 1} \right).\left( { – x} \right) = 0\\
\Leftrightarrow \left[ \begin{array}{l}
x + 1 = 0\\
– x = 0
\end{array} \right. \Leftrightarrow \left[ \begin{array}{l}
x = – 1\\
x = 0
\end{array} \right.
\end{array}\)