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\(\left(2,4x-36\right)=-1.\frac{12}{7}\)
\(\left(2,4x-36\right)=\frac{-12}{7}\)
\(2,4x=\frac{-12}{7}+36\)
\(2,4x=\frac{240}{7}\)
\(x=\frac{240}{7}:2,4\)
\(x=\frac{100}{7}\)
\(\left(2,4x-36\right):1\frac{5}{7}=-1\)
2,4x - 36 = -1 . \(\frac{12}{7}=\) -12/7
2,4x = -12/7 + 36 = 240/7
x = 240/7 : 2,4 = 100/7
a) \(\frac{3}{x-5}=\frac{-4}{x+2}\)(ĐKXĐ: \(x\ne5;x\ne-2\))
\(\Rightarrow3\left(x+2\right)=-4\left(x-5\right)\)
\(\Leftrightarrow3x+6=-4x+20\)
\(\Leftrightarrow7x=14\)
\(\Leftrightarrow x=2\)(thỏa mãn ĐKXĐ)
b) \(2,4x-36=-\frac{7}{12}\)
\(\Leftrightarrow2,4x=\frac{425}{12}\)
\(\Leftrightarrow x=\frac{2125}{144}\)
c) \(\left(\frac{19}{5}-2x\right).\frac{4}{3}=\frac{40}{7}\)
\(\Leftrightarrow\frac{19}{5}-2x=\frac{30}{7}\)
\(\Leftrightarrow2x=-\frac{17}{35}\)
\(\Leftrightarrow x=-\frac{17}{70}\)
b) \(\left(2,4.x-36\right)\div1\frac{5}{7}=-1\)
\(\left(2,4.x-36\right)=-1.\frac{12}{7}\)
\(2,4.x-36=-\frac{12}{7}\)
\(2,4.x=-\frac{12}{7}+36\)
\(2,4.x=\frac{240}{7}\)
\(x=\frac{240}{7}\div2,4\)
\(x=\frac{100}{7}\)
a. 7/9 - 16/9 = -9/9 = -1
b. 2/-15 + 7/10 = 17/30
c. (4 2/3 - 4 3/4) : -5/12 - 4/5
= (14/3 - 19/4) : (-5/12) - 4/5
= -1/12 : (-5/12) - 4/5
= 1/5 - 4/5
= -3/5
Ta có: \(\dfrac{7}{15}+\dfrac{9}{10}+\dfrac{8}{15}+\dfrac{1}{10}+\dfrac{-20}{10}+\dfrac{1}{157}\)
\(=\left(\dfrac{7}{15}+\dfrac{8}{15}\right)+\left(\dfrac{9}{10}+\dfrac{1}{10}+\dfrac{-20}{10}\right)+\dfrac{1}{157}\)
\(=1+\left(-1\right)+\dfrac{1}{157}\)
\(=0+\dfrac{1}{157}=\dfrac{1}{157}.\)
Ta có: \(\dfrac{7}{15}+\dfrac{9}{10}+\dfrac{8}{15}+\dfrac{1}{10}+\dfrac{-20}{10}+\dfrac{1}{157}\)
= \(\left(\dfrac{7}{15}+\dfrac{8}{15}\right)+\left(\dfrac{9}{10}+\dfrac{1}{10}+\dfrac{-20}{10}\right)+\dfrac{1}{157}\)
= \(\dfrac{7+8}{15}+\dfrac{10-20}{10}+\dfrac{1}{157}\)
= 1-1+\(\dfrac{1}{157}\)= 0 + \(\dfrac{1}{157}\) = \(\dfrac{1}{157}\)