## Giúp em bài 4 với ạ.Em cảm ơn nhiều lắm ạ

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Giúp em bài 4 với ạ.Em cảm ơn nhiều lắm ạ

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8 tháng 2020-11-01T16:35:16+00:00 1 Answers 49 views 0

$\begin{array}{l} a)\left( {x – 5} \right)\left( {x – 60} \right) = 0\\ \Rightarrow \left[ \begin{array}{l} x – 5 = 0\\ x – 60 = 0 \end{array} \right.\\ \Rightarrow \left[ \begin{array}{l} x = 5\\ x = 60 \end{array} \right.\\ \text{Vậy}\,x = 5\,\text{hoặc}\,x = 60\\ b)\left( {2x – 8} \right)\left( {5x – 155} \right) = 0\\ \Rightarrow \left[ \begin{array}{l} 2x – 8 = 0\\ 5x – 155 = 0 \end{array} \right.\\ \Rightarrow \left[ \begin{array}{l} x = 4\\ x = 31 \end{array} \right.\\ \text{Vậy}\,x = 4\,\text{hoặc}\,x = 31\\ c)\left( {132 – 4x} \right)\left( {x + 20} \right) = 0\\ \Rightarrow \left[ \begin{array}{l} 132 – 4x = 0\\ x + 20 = 0 \end{array} \right.\\ \Rightarrow \left[ \begin{array}{l} x = 33\\ x = – 20 \end{array} \right.\\ \text{Vậy}\,x = 33\,\text{hoặc}\,x = – 20\\ d)\left( {275 – 11x} \right)\left( {x – 20} \right) + 6.7 = 42\\ \Rightarrow \left( {275 – 11x} \right)\left( {x – 20} \right) = 0\\ \Rightarrow \left[ \begin{array}{l} 275 – 11x = 0\\ x – 20 = 0 \end{array} \right.\\ \Rightarrow \left[ \begin{array}{l} x = 25\\ x = 20 \end{array} \right.\\ \text{Vậy}\,x = 25\,\text{hoặc}\,x = 20\\ e)\left( {x – 5} \right)\left( {9x – 27.3} \right) = 5.8 – 5.8\\ \Rightarrow \left( {x – 5} \right)\left( {9x – 81} \right) = 0\\ \Rightarrow \left[ \begin{array}{l} x – 5 = 0\\ 9x – 81 = 0 \end{array} \right.\\ \Rightarrow \left[ \begin{array}{l} x = 5\\ x = 9 \end{array} \right.\\ \text{Vậy}\,x = 5\,\text{hoặc}\,x = 9\\ f)\left( {6x – 4} \right)\left( {x + 2} \right) = 90 – 180:2\\ \Rightarrow \left( {6x – 4} \right)\left( {x + 2} \right) = 0\\ \Rightarrow \left[ \begin{array}{l} 6x – 4 = 0\\ x + 2 = 0 \end{array} \right.\\ \Rightarrow \left[ \begin{array}{l} x = \dfrac{4}{6} = \dfrac{2}{3}\\ x = – 2 \end{array} \right.\\ \text{Vậy}\,x = \dfrac{2}{3}\,\text{hoặc}\,x = – 2 \end{array}$