Giúp em bài 4 với ạ.Em cảm ơn nhiều lắm ạ Question Giúp em bài 4 với ạ.Em cảm ơn nhiều lắm ạ in progress 0 Môn Toán Latifah 4 years 2020-11-01T16:35:16+00:00 2020-11-01T16:35:16+00:00 1 Answers 63 views 0
Answers ( )
Đáp án:
$\begin{array}{l}
a)\left( {x – 5} \right)\left( {x – 60} \right) = 0\\
\Rightarrow \left[ \begin{array}{l}
x – 5 = 0\\
x – 60 = 0
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
x = 5\\
x = 60
\end{array} \right.\\
\text{Vậy}\,x = 5\,\text{hoặc}\,x = 60\\
b)\left( {2x – 8} \right)\left( {5x – 155} \right) = 0\\
\Rightarrow \left[ \begin{array}{l}
2x – 8 = 0\\
5x – 155 = 0
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
x = 4\\
x = 31
\end{array} \right.\\
\text{Vậy}\,x = 4\,\text{hoặc}\,x = 31\\
c)\left( {132 – 4x} \right)\left( {x + 20} \right) = 0\\
\Rightarrow \left[ \begin{array}{l}
132 – 4x = 0\\
x + 20 = 0
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
x = 33\\
x = – 20
\end{array} \right.\\
\text{Vậy}\,x = 33\,\text{hoặc}\,x = – 20\\
d)\left( {275 – 11x} \right)\left( {x – 20} \right) + 6.7 = 42\\
\Rightarrow \left( {275 – 11x} \right)\left( {x – 20} \right) = 0\\
\Rightarrow \left[ \begin{array}{l}
275 – 11x = 0\\
x – 20 = 0
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
x = 25\\
x = 20
\end{array} \right.\\
\text{Vậy}\,x = 25\,\text{hoặc}\,x = 20\\
e)\left( {x – 5} \right)\left( {9x – 27.3} \right) = 5.8 – 5.8\\
\Rightarrow \left( {x – 5} \right)\left( {9x – 81} \right) = 0\\
\Rightarrow \left[ \begin{array}{l}
x – 5 = 0\\
9x – 81 = 0
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
x = 5\\
x = 9
\end{array} \right.\\
\text{Vậy}\,x = 5\,\text{hoặc}\,x = 9\\
f)\left( {6x – 4} \right)\left( {x + 2} \right) = 90 – 180:2\\
\Rightarrow \left( {6x – 4} \right)\left( {x + 2} \right) = 0\\
\Rightarrow \left[ \begin{array}{l}
6x – 4 = 0\\
x + 2 = 0
\end{array} \right.\\
\Rightarrow \left[ \begin{array}{l}
x = \dfrac{4}{6} = \dfrac{2}{3}\\
x = – 2
\end{array} \right.\\
\text{Vậy}\,x = \dfrac{2}{3}\,\text{hoặc}\,x = – 2
\end{array}$