cau dau tien la sao

1,2 : 3,24 = \(\frac{12}{10}\):  \(\frac{324}{100}\)= \(\frac{12}{10}\)x \(\frac{100}{324}\)= \(\frac{10}{27}\)

\(\frac{2}{7}\) : 0,42 = \(\frac{2}{7}\):  \(\frac{42}{100}\)= \(\frac{2}{7}\)x  \(\frac{100}{42}\)=  \(\frac{100}{147}\)

Cau tren ko hieu ban viet nhu the nao nen mk ko lam duoc , kick mk nhe

Bấm máy tính:

E = \(\frac{4}{3}+\frac{1}{4}+\frac{3}{5}:\frac{4}{5}\)

E = \(\frac{4}{3}+\frac{1}{4}+\frac{3}{4}\)

E = \(\frac{7}{3}\)

Vậy E = \(\frac{7}{3}\)

\(E=\frac{0,8:\left(\frac{4}{5}.1,25\right)}{0,64-\frac{1}{25}}+\frac{\left(1,08-\frac{2}{25}\right):\frac{4}{7}}{\left(6\frac{5}{9}-3\frac{1}{4}\right).2\frac{2}{17}}+\left(1,2.0,5\right):\frac{4}{5}\)

\(E=\frac{\frac{4}{5}:\frac{4}{5}:1,25}{\frac{16}{25}-\frac{1}{25}}+\frac{\left(\frac{27}{25}-\frac{2}{25}\right).\frac{7}{4}}{\left(\frac{59}{9}-\frac{13}{4}\right).\frac{36}{17}}+\frac{6}{5}.\frac{1}{2}.\frac{5}{4}\)

\(E=\frac{1:\frac{5}{4}}{\frac{3}{5}}+\frac{1.\frac{7}{4}}{\frac{119}{36}.\frac{36}{17}}+\frac{3}{4}\)

\(E=\frac{4}{5}.\frac{5}{3}+\frac{\frac{7}{4}}{7}+\frac{3}{4}\)

\(E=\frac{4}{3}+\frac{7}{4}.\frac{1}{7}+\frac{3}{4}\)

\(E=\frac{4}{3}+\frac{1}{4}+\frac{3}{4}\)

\(E=\frac{4}{3}+1=\frac{7}{3}\)

a)\(\frac{2}{3}:\frac{4}{9}+\frac{1}{3}:\frac{4}{9}\)

=\(\frac{4}{9}:\left(\frac{2}{3}+\frac{1}{3}\right)\)

=\(\frac{4}{9}:1=\frac{4}{9}\)

b

a 9/4

b 49/40

c 36/35

d 144/441

\(a,4\frac{5}{9}:\frac{\left(-5\right)}{7}+\frac{4}{9}:\frac{-5}{7}\)

\(=\frac{41}{9}.\frac{-7}{5}+\frac{4}{9}.\frac{-7}{5}\)

\(=\frac{-7}{5}.\left(\frac{41}{9}+\frac{4}{9}\right)\)

\(=-\frac{7}{9}.5\)

\(=-7\)

a)Bn Kaito Kid làm rùi!

B)Không viết lại đề

\(=\frac{11}{7}\cdot\left(-\frac{3}{5}+\frac{4}{9}-\frac{2}{5}+\frac{5}{9}\right)=\frac{11}{7}\cdot0=0\)

c)Không viết lại đề

\(A=\left(2+4+...+100\right)\left(\frac{3}{5}\cdot\frac{10}{7}-\frac{6}{7}\right):\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{100}\right)\)

\(=\left(2+4+6+...+100\right)\cdot0\cdot\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{100}\right)=0\)

\(=\frac{7}{6}\cdot\left(\frac{3}{26}-\frac{3}{13}+\frac{1}{10}-\frac{8}{5}\right)=\frac{7}{6}\left(\frac{-3}{26}+\frac{-17}{10}\right)=\frac{7}{6}\cdot\frac{236}{130}=\frac{413}{195}\)

D)

Dòng trên chữ D) là phần c)

Dưới phần c) là phần d) nha!(Lỗi đánh máy)

ta có:4/5:(4/5*5/4)/16/25-1/25+(27/25-2/25):4/7/(59/9-13/4)*36/17+6/5*1/2

       =4/5:3/5+7/4:7+3/5

        =4/3+1/4+3/5

         =3/2+3/5=21/10

Bài 2: 

a: =>x/7=1/21

=>x=1/3

c: =>x(3x-2)=0

=>x=0 hoặc x=2/3

Bài1:

a: \(=\left(-\dfrac{7}{3}\right)^{3-2}=\dfrac{-7}{3}\)

b: \(=\left(-\dfrac{4}{9}\right)^{1-3}=\left(-\dfrac{4}{9}\right)^{-2}=\dfrac{81}{16}\)

c: \(=\left(\dfrac{1}{5}\right)^{10-7}=\left(\dfrac{1}{5}\right)^3=\dfrac{1}{125}\)

1. 

a) (—7/3)³:(—7/3)²=(—7/3)^3–2=—7/3

b) (—4/9):(—4/9)³= (—4/9)^1–3=(—4/9)^—2=81/16

c) (1/5)¹⁰:(1/5)⁷=(1/5)^10–7=(1/5)³=1/125

2. 

a) —x/7 =1/—21

==> —x.(—21)=7.1

==> —x.(—21)=7

==> —x=7:(—21)

==> —x=—1/3

==> x=1/3

b) 4 2/5 . 0,5–1 3/7= 22/5 . 1/2 —10/7= 22.1/5.2–10/7=  11/5 —10/7= 77/35 — 50/35= 27/35

c) 3x²–2x=0

==> x³(3–2)=0

x³.1=0

x³=0:1

x³=0

==> x=0

c) 9x²–1=0

9x²=0+1

9x²=1

x²=1:9

x²=1/9

x²=1²/3² hoặc x²=(—1/3)²

Vậy x=1/3 hoặc x=—1/3