Question

Bài 2: Tính

e, \(\dfrac{3}{11}\) . ( 2\(\dfrac{2}{3}\) - 1,75 )

f, ( \(\dfrac{3}{4}\) + 0,5 ) : (\(\dfrac{4}{5}\) - 0,6)

Bài 3:Tìm x

a, x - \(\dfrac{17}{36}\) = \(\dfrac{-15}{16}\) . \(\dfrac{4}{27}\)

b, \(\dfrac{4}{15}\) - x = \(\dfrac{-9}{12}\) . \(\dfrac{-4}{3}\)

c, | x - 2 | = \(\dfrac{-9}{12}\) . \(\dfrac{-4}{3}\)

d, x - \(\dfrac{3^2}{25}\) = (\(\dfrac{-4}{5}\))^2

Bài 4: Tìm x

a, (x + 1,5) : 3\(\dfrac{1}{5}\) = \(\dfrac{-5}{8}\)

b, (8\(\dfrac{4}{5}\)  x - 50) : 0,4 = 51

c, ( x + \(\dfrac{5}{6}\) ) . 2 \(\dfrac{2}{5}\) - 1\(\dfrac{1}{4}\) = 35%

d, | x - 1 | - \(\dfrac{12}{16}\) = 25%

Answer 1

Bài 2:

\(e)\dfrac{3}{11}\cdot\left(2\dfrac{2}{3}-1,75\right)\\ =\dfrac{3}{11}\cdot\left(\dfrac{8}{3}-\dfrac{7}{4}\right)\\ =\dfrac{3}{11}\cdot\dfrac{11}{12}\\ =\dfrac{1}{4}\\ f)\left(\dfrac{3}{4}+0,5\right):\left(\dfrac{4}{5}-0,6\right)\\ =\left(\dfrac{3}{4}+\dfrac{1}{2}\right):\left(\dfrac{4}{5}-\dfrac{3}{5}\right)\\ =\left(\dfrac{3}{4}+\dfrac{2}{4}\right):\dfrac{1}{5}\\ =\dfrac{5}{4}\cdot5\\ =\dfrac{25}{4}\)

Answer 2

Bài 3:

a: \(x-\dfrac{17}{36}=\dfrac{-15}{16}\cdot\dfrac{4}{27}\)

=>\(x-\dfrac{17}{36}=-\dfrac{4}{16}\cdot\dfrac{15}{27}=-\dfrac{1}{4}\cdot\dfrac{5}{9}=-\dfrac{5}{36}\)

=>\(x=-\dfrac{5}{36}+\dfrac{17}{36}=\dfrac{12}{36}=\dfrac{1}{3}\)

b: \(\dfrac{4}{15}-x=\dfrac{-9}{12}\cdot\dfrac{-4}{3}\)

=>\(\dfrac{4}{15}-x=\dfrac{36}{36}=1\)

=>\(x=\dfrac{4}{15}-1=-\dfrac{11}{15}\)

c: \(\left|x-2\right|=\dfrac{-9}{12}\cdot\dfrac{-4}{3}\)

=>\(\left|x-2\right|=\dfrac{-36}{-36}=1\)

=>\(\left[{}\begin{matrix}x-2=1\\x-2=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)

d: \(x-\dfrac{3^2}{25}=\left(-\dfrac{4}{5}\right)^2\)

=>\(x-\dfrac{9}{25}=\dfrac{16}{25}\)

=> \(x=\dfrac{16}{25}+\dfrac{9}{25}=\dfrac{25}{25}=1\)

Bài 4:

a: \(\left(x+1,5\right):3\dfrac{1}{5}=-\dfrac{5}{8}\)

=>\(\left(x+1,5\right):\dfrac{16}{5}=-\dfrac{5}{8}\)

=>\(x+1,5=-\dfrac{5}{8}\cdot\dfrac{16}{5}=-\dfrac{16}{8}=-2\)

=>x=-2-1,5=-3,5

b: \(\left(8\dfrac{4}{5}x-50\right):0,4=51\)

=>\(8,8x-50=51\cdot0,4=20,4\)

=>\(8,8x=50+20,4=70,4\)

=>\(x=\dfrac{70.4}{8.8}=8\)

c: \(\left(x+\dfrac{5}{6}\right)\cdot2\dfrac{2}{5}-1\dfrac{1}{4}=35\%\)

=>\(\left(x+\dfrac{5}{6}\right)\cdot\dfrac{12}{5}=35\%+1,25=1,25+0,35=1,6=\dfrac{8}{5}\)

=>\(x+\dfrac{5}{6}=\dfrac{8}{5}:\dfrac{12}{5}=\dfrac{8}{12}=\dfrac{2}{3}\)

=>\(x=\dfrac{2}{3}-\dfrac{5}{6}=\dfrac{4}{6}-\dfrac{5}{6}=-\dfrac{1}{6}\)

d: \(\left|x-1\right|-\dfrac{12}{16}=25\%\)

=>\(\left|x-1\right|=25\%+\dfrac{12}{16}=1\)

=>\(\left[{}\begin{matrix}x-1=1\\x-1=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=0\end{matrix}\right.\)