1) \(-\frac{2}{3}\left(x-\frac{1}{4}\right)=\frac{1}{3}\left(2x-1\right)\)

\(-\frac{2}{3}x+\frac{1}{6}=\frac{2}{3}x-\frac{1}{3}\)

\(-\frac{2}{3}x-\frac{2}{3}x=-\frac{1}{3}-\frac{1}{6}\)

\(-\frac{4}{3}x=-\frac{1}{2}\)

\(x=\left(-\frac{1}{2}\right):\left(-\frac{4}{3}\right)\)

\(x=\frac{3}{8}\)

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

- \(\dfrac{2}{3}x\) + \(\dfrac{1}{6}\) = \(\dfrac{2}{3}x\) - \(\dfrac{1}{3}\)

\(\dfrac{2}{3}x+\dfrac{2}{3}x\) = \(\dfrac{1}{6}+\dfrac{1}{3}\)

\(\dfrac{4}{3}x=\) \(\dfrac{1}{2}\)

   \(x\) = \(\dfrac{1}{2}\) : \(\dfrac{4}{3}\)

   \(x\) = \(\dfrac{3}{8}\) 

Vậy  \(x=\dfrac{3}{8}\) 

Em ghi đề rõ ràng lại nhé

Mik nghĩ môn toán thì sẽ khó hơn vì nó lí luận dài dòng phức tạp nhưng cả hai môn toán và anh đều có tầm quan trọng như nhau 

Vì a;a+1;a+2;a+3 là bốn số nguyên liên tiếp

nên \(a\left(a+1\right)\left(a+2\right)\left(a+3\right)⋮4!\)

=>\(A⋮4\)

File: undefined 

câu hỏi của bạn đâu?

Bài 2:

a: \(\dfrac{5}{2}-x=\dfrac{27}{8}\)

=>\(x=\dfrac{5}{2}-\dfrac{27}{8}=\dfrac{20}{8}-\dfrac{27}{8}=-\dfrac{7}{8}\)

b: \(-\dfrac{1}{3}+\dfrac{4}{10}x=0,2\)

=>\(\dfrac{2}{5}x=0,2+\dfrac{1}{3}=\dfrac{1}{5}+\dfrac{1}{3}=\dfrac{8}{15}\)

=>\(x=\dfrac{8}{15}:\dfrac{2}{5}=\dfrac{8}{15}\cdot\dfrac{5}{2}=\dfrac{40}{30}=\dfrac{4}{3}\)

c: \(\left(3x+2\right)^2=\dfrac{25}{49}\)

=>\(\left[{}\begin{matrix}3x+2=\dfrac{5}{7}\\3x+2=-\dfrac{5}{7}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}3x=\dfrac{5}{7}-2=-\dfrac{9}{7}\\3x=-\dfrac{5}{7}-2=-\dfrac{19}{7}\end{matrix}\right.\)

=>\(\left[{}\begin{matrix}x=-\dfrac{3}{7}\\x=-\dfrac{19}{21}\end{matrix}\right.\)

Bài 1:

a: \(\dfrac{5}{6}+\dfrac{-11}{30}+\dfrac{7}{5}\)

\(=\dfrac{25}{30}-\dfrac{11}{30}+\dfrac{42}{30}=\dfrac{56}{30}=\dfrac{28}{15}\)

b: \(\left(-\dfrac{4}{5}\right)^2\cdot\dfrac{57}{2}+\dfrac{-7}{2}\cdot\left(-\dfrac{4}{5}\right)^2\)

\(=\left(-\dfrac{4}{5}\right)^2\left(\dfrac{57}{2}-\dfrac{7}{2}\right)=\dfrac{16}{25}\cdot25=16\)

c: \(\left(\dfrac{7}{25}-1\dfrac{2}{9}\right)-\left(\dfrac{23}{54}-\dfrac{18}{25}\right)+\dfrac{-31}{54}\)

\(=\dfrac{7}{25}-\dfrac{11}{9}-\dfrac{23}{54}+\dfrac{18}{25}-\dfrac{31}{54}\)

\(=\left(\dfrac{7}{25}+\dfrac{18}{25}\right)-\left(\dfrac{23}{54}+\dfrac{31}{54}\right)-\dfrac{11}{9}=1-1-\dfrac{11}{9}=-\dfrac{11}{9}\)

Câu 2:

a: \(x-\dfrac{1}{3}=\dfrac{5}{2}\)

=>\(x=\dfrac{5}{2}+\dfrac{1}{3}=\dfrac{15}{6}+\dfrac{2}{6}=\dfrac{17}{6}\)

b: \(\left(1-2x\right)^2=\dfrac{4}{9}\)

=>\(\left(2x-1\right)^2=\dfrac{4}{9}\)

=>\(\left[{}\begin{matrix}2x-1=\dfrac{2}{3}\\2x-1=-\dfrac{2}{3}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=\dfrac{5}{3}\\2x=\dfrac{1}{3}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{6}\\x=\dfrac{1}{6}\end{matrix}\right.\)

Câu 1:

a: \(-\dfrac{4}{3}+\dfrac{3}{2}:\dfrac{9}{4}\)

\(=\dfrac{-4}{3}+\dfrac{3}{2}\cdot\dfrac{4}{9}\)

\(=\dfrac{-4}{3}+\dfrac{2}{3}=-\dfrac{2}{3}\)

b: \(\left(\dfrac{10}{9}+\dfrac{13}{7}\right)-\left(\dfrac{19}{9}-\dfrac{1}{7}\right)\)

\(=\dfrac{10}{9}+\dfrac{13}{7}-\dfrac{19}{9}+\dfrac{1}{7}=\left(\dfrac{10}{9}-\dfrac{19}{9}\right)+\left(\dfrac{13}{7}+\dfrac{1}{7}\right)\)

=-1+2

=1

juan ko anh thịnh

1/5 giờ=12 phút

\(1\dfrac{1}{3}phút=80\left(giây\right)\)

7m45cm=745cm

\(\dfrac{1}{5}giờ=\dfrac{1}{5}.60\left(phút\right)=12\left(phút\right)\)

\(1\dfrac{1}{3}phút=\dfrac{4}{3}.60\left(giây\right)=80\left(giây\right)\)

\(7m45cm=700+45\left(cm\right)=745\left(cm\right)\)

\(45ha50dam=4500+500\left(m\right)=5000\left(m\right)\)

\(-\dfrac{4}{3}+\dfrac{3}{2}:\dfrac{27}{12}=\dfrac{-4}{3}+\dfrac{3}{2}\cdot\dfrac{12}{27}\)

\(=\dfrac{-4}{3}+\dfrac{3}{2}\cdot\dfrac{4}{9}=\dfrac{-4}{3}+\dfrac{2}{3}=-\dfrac{2}{3}\)

a: Vì \(32⋮4\)

nên \(32\cdot27\cdot14⋮4\)

=>\(A⋮4\)

b: \(20⋮4\)

=>\(20\cdot43\cdot41⋮4\)

=>\(B⋮4\)

c: \(124⋮4\)

=>\(124\cdot45\cdot29⋮4\)

=>\(C⋮4\)

d: \(22\cdot2=44⋮4\)

=>\(22\cdot127\cdot2\cdot15⋮4\)

=>\(D⋮4\)

a) A = 32 . 27 . 14

= 4 . 8 . 27 . 14 chia hết cho 4

b) B = 20 . 43 . 41

= 4 . 5 . 43 . 41 chia hết cho 4

c) C = 124 . 45 . 29

= 4 . 31 . 45 . 29 chia hết cho 4

d) D = 22 . 127 . 2 . 15

= 2 . 11 . 127 . 2 . 15

= ( 2 . 2 ) . 11 . 127 . 15

= 4 . 11 . 127 . 15 chia hết cho 4

Vậy tất cả các tích trên đều chia hết cho 4