Giải các phương trình sau: a, (x-3/5 +1)/4=(2x/3 -1/2)/6 b, (5x +x+2/2)/9 -x=(x+3/5 +15)/12 -2 21/11/2021 Bởi Katherine Giải các phương trình sau: a, (x-3/5 +1)/4=(2x/3 -1/2)/6 b, (5x +x+2/2)/9 -x=(x+3/5 +15)/12 -2
Đáp án: a) x=3 Giải thích các bước giải: \(\begin{array}{l}a)\left( {\dfrac{{x – 3}}{5} + 1} \right):4 = \left( {\dfrac{{2x}}{3} – \dfrac{1}{2}} \right):6\\ \to \left( {\dfrac{{x – 3 + 5}}{5}} \right).\dfrac{1}{4} = \left( {\dfrac{{4x – 3}}{6}} \right).\dfrac{1}{6}\\ \to \dfrac{{x + 2}}{{20}} = \dfrac{{4x – 3}}{{36}}\\ \to 36x + 72 = 80x – 60\\ \to 44x = 132\\ \to x = 3\\b)\left( {5x + \dfrac{{x + 2}}{2}} \right):9 – x = \left( {\dfrac{{x + 3}}{5} + 15} \right):12 – 2\\ \to \dfrac{{10x + x + 2}}{2}.\dfrac{1}{9} – x = \dfrac{{x + 3 + 75}}{5}.\dfrac{1}{{12}} – 2\\ \to \dfrac{{11x + 2}}{{18}} – x = \dfrac{{x + 78}}{{60}} – 2\\ \to \dfrac{{11x + 2 – 18x}}{{18}} = \dfrac{{x + 78 – 120}}{{60}}\\ \to \dfrac{{2 – 6x}}{{18}} = \dfrac{{x – 42}}{{60}}\\ \to 120 – 360x = 18x – 756\\ \to 378x = 876\\ \to x = \dfrac{{146}}{{63}}\end{array}\) Bình luận
Đáp án:
a) x=3
Giải thích các bước giải:
\(\begin{array}{l}
a)\left( {\dfrac{{x – 3}}{5} + 1} \right):4 = \left( {\dfrac{{2x}}{3} – \dfrac{1}{2}} \right):6\\
\to \left( {\dfrac{{x – 3 + 5}}{5}} \right).\dfrac{1}{4} = \left( {\dfrac{{4x – 3}}{6}} \right).\dfrac{1}{6}\\
\to \dfrac{{x + 2}}{{20}} = \dfrac{{4x – 3}}{{36}}\\
\to 36x + 72 = 80x – 60\\
\to 44x = 132\\
\to x = 3\\
b)\left( {5x + \dfrac{{x + 2}}{2}} \right):9 – x = \left( {\dfrac{{x + 3}}{5} + 15} \right):12 – 2\\
\to \dfrac{{10x + x + 2}}{2}.\dfrac{1}{9} – x = \dfrac{{x + 3 + 75}}{5}.\dfrac{1}{{12}} – 2\\
\to \dfrac{{11x + 2}}{{18}} – x = \dfrac{{x + 78}}{{60}} – 2\\
\to \dfrac{{11x + 2 – 18x}}{{18}} = \dfrac{{x + 78 – 120}}{{60}}\\
\to \dfrac{{2 – 6x}}{{18}} = \dfrac{{x – 42}}{{60}}\\
\to 120 – 360x = 18x – 756\\
\to 378x = 876\\
\to x = \dfrac{{146}}{{63}}
\end{array}\)
Đáp án:
Giải thích các bước giải: