Question

[Hoàng Minh duc]

 

Answer 1

[Nguyễn Lê Phước Thịnh]

Bài 2:

a: \(45\%\cdot x-0,385=-1,685\)

=>\(0,45x=-1,685+0,385=-1,3\)

=>\(x=-\dfrac{1.3}{0,45}=-\dfrac{26}{9}\)

b: \(\left(3\dfrac{1}{4}+2x\right)\cdot\dfrac{2}{3}=2\)

=>\(2x+\dfrac{13}{4}=2:\dfrac{2}{3}=3\)

=>\(2x=3-\dfrac{13}{4}=-\dfrac{1}{4}\)

=>\(x=-\dfrac{1}{4}:2=-\dfrac{1}{8}\)

c: \(\dfrac{3}{4}+\dfrac{1}{4}:x=-3\)

=>\(\dfrac{1}{4}:x=-3-\dfrac{3}{4}=-\dfrac{15}{4}\)

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

d: \(2x-0,75=-\dfrac{7}{12}\)

=>\(2x=-\dfrac{7}{12}+0,75=\dfrac{2}{12}\)

=>\(x=\dfrac{1}{12}\)

e: \(\dfrac{4}{9}-\dfrac{7}{12}x=\dfrac{1}{3}\)

=>\(\dfrac{7}{12}x=\dfrac{4}{9}-\dfrac{1}{3}=\dfrac{1}{9}\)

=>\(x=\dfrac{1}{9}:\dfrac{7}{12}=\dfrac{1}{9}\cdot\dfrac{12}{7}=\dfrac{4}{21}\)

Bài 1:

a: \(\left(\dfrac{7}{5}+\dfrac{-5}{11}\right)-\left(\dfrac{6}{11}-\dfrac{3}{5}\right)-2023^0\)

\(=\dfrac{7}{5}-\dfrac{5}{11}-\dfrac{6}{11}+\dfrac{3}{5}-1\)

\(=2-1-1=0\)

b: \(\dfrac{2}{-9}\cdot\dfrac{7}{15}+\dfrac{-2}{9}\cdot\dfrac{8}{15}+1\dfrac{2}{3}\)

\(=\dfrac{-2}{9}\left(\dfrac{7}{15}+\dfrac{8}{15}\right)+\dfrac{5}{3}\)

\(=-\dfrac{2}{9}+\dfrac{5}{3}=\dfrac{13}{9}\)

c: \(\dfrac{1}{3}+\dfrac{-7}{12}+\dfrac{2}{3}+\dfrac{-5}{12}\)

\(=\left(\dfrac{1}{3}+\dfrac{2}{3}\right)+\left(-\dfrac{7}{12}-\dfrac{5}{12}\right)\)

=1-1

=0

d: \(\dfrac{3}{7}\cdot\dfrac{-9}{13}+\dfrac{3}{7}\cdot\dfrac{-4}{13}+1\dfrac{3}{7}\)

\(=\dfrac{3}{7}\left(-\dfrac{9}{13}-\dfrac{4}{13}\right)+1+\dfrac{3}{7}\)

\(=-\dfrac{3}{7}+1+\dfrac{3}{7}\)

=1

e: \(\dfrac{2}{-5}-\left(\dfrac{5}{2}-\dfrac{12}{5}\right)\)

\(=-\dfrac{2}{5}-\dfrac{5}{2}+\dfrac{12}{5}=2-\dfrac{5}{2}=-\dfrac{1}{2}\)