a) \(\dfrac{5}{6}-\dfrac{2}{14}\)

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

\(=\dfrac{35}{42}-\dfrac{6}{42}\)

\(=\dfrac{29}{42}\)

b) \(\dfrac{5}{20}-\dfrac{1}{6}\)

\(=\dfrac{1}{4}-\dfrac{1}{6}\)

\(=\dfrac{3}{12}-\dfrac{2}{12}\)

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

c) \(\dfrac{5}{9}-\dfrac{3}{12}\)

\(=\dfrac{5}{9}-\dfrac{1}{4}\)

\(=\dfrac{20}{36}-\dfrac{9}{36}\)

\(=\dfrac{11}{36}\)

d) \(8-\dfrac{4}{6}\)

\(=\dfrac{48}{6}-\dfrac{4}{6}\)

\(=\dfrac{44}{6}=\dfrac{22}{3}\).

5(3x+5)-4(2x-3)=5x+3(2x+12)+1

15x+25-8x+12=5x+6x+36+1

7x+37=11x+37

7x+37-11x-37=0

-4x=0

x=0

you are my angel~

Câu 1: 

a: Phân số lớn nhất là 11/12

b: Phân số nhỏ nhất là 2/3

Câu 2: 

a: \(\Leftrightarrow y=\dfrac{1}{2}-\dfrac{1}{4}=\dfrac{1}{4}\)

b: \(\Leftrightarrow y=\dfrac{8}{12}-\dfrac{3}{12}+\dfrac{5}{12}=\dfrac{10}{12}=\dfrac{5}{6}\)

lớn nhất là 11/12

bé nhất là 2/3

y1= 1/4

y2= 5/12

a) \(\left(2x+3\right).\left(\frac{1}{2}.x-\frac{3}{2}\right)=0\)

\(\Rightarrow\orbr{\begin{cases}2x+3=0\\\frac{1}{2}.x-\frac{3}{2}=0\end{cases}}\) \(\Rightarrow\orbr{\begin{cases}2x=-3\\\frac{1}{2}.x=\frac{3}{2}\end{cases}}\Rightarrow\orbr{\begin{cases}x=-\frac{3}{2}\\x=\frac{3}{2}:\frac{1}{2}\end{cases}}\) \(\Rightarrow\orbr{\begin{cases}x=-\frac{3}{2}\\x=3\end{cases}}\)

Vậy x = \(-\frac{3}{2}\) hoặc x = 3

b)\(\left(\frac{1}{2}-x\right)^2=\frac{64}{49}\)

\(\Rightarrow\left(\frac{1}{2}-x\right)^2=\left(\frac{8}{7}\right)^2\) hoặc \(\left(\frac{1}{2}-x\right)^2=\left(-\frac{8}{7}\right)^2\)

\(\Rightarrow\orbr{\begin{cases}\frac{1}{2}-x=\frac{8}{7}\\\frac{1}{2}-x=-\frac{8}{7}\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{1}{2}-\frac{8}{7}\\x=\frac{1}{2}+\frac{8}{7}\end{cases}}\Rightarrow\orbr{\begin{cases}x=-\frac{9}{14}\\x=\frac{23}{14}\end{cases}}\)

Vậy x = \(-\frac{9}{14}\) hoặc x = \(\frac{23}{14}\)

c) \(\frac{1}{2}.\left(x-4,5\right)=\frac{3}{4}.x=\frac{5}{12}\) ( câu này mik ko hiểu cho lắm)

k mik nha mn!

doi mik sua

la cong 3/4

Trả lời:

\(10+11+12+13+14+15+16+17+18+19+20\)

\(=\left(10+20\right)+\left(11+19\right)+\left(12+18\right)+\left(13+17\right)+\left(14+16\right)+15\)

\(=30+30+30+30+30+15\)

\(=165\)

\(1+2+3+4+5+6+7+8+9\)

\(=\left(1+9\right)+\left(2+8\right)+\left(3+7\right)+\left(4+6\right)+5\)

\(=10+10+10+10+5\)

\(=45\)

10+11+12+13+14+15+16+17+18+19+20

(10+20)+(11+19)+(12+18)+(13+17)+(14+16)+15

30+30+30+30+30+15

165

\(a,\text{10 + 11 + 12 + 13 + 14 + 16 + 17 + 18 + 19 + 20}\)

\(=\left(10+20\right)+\left(11+19\right)+\left(12+18\right)+\left(13+17\right)+\left(14+16\right)\)

\(=30+30+30+30+30\)

\(=30\times5\)

\(=150.\)

\(b,\text{1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9}\)

\(=\left(1+9\right)+\left(2+8\right)+\left(3+7\right)+\left(4+6\right)+5\)

\(=10+10+10+10+5\)

\(=45.\)

a)=\(\frac{-2.4}{5.7}+\frac{-3.2}{5.7}+\frac{-3}{5}\)

=\(\frac{-2.4}{5.7}+\frac{-2.3}{5.7}+\frac{-3}{5}\)

=\(\frac{-2}{5}\left(\frac{4+3}{7}\right)+\frac{-3}{5}\)

=\(\frac{-2}{5}.1+\frac{-3}{5}\)

=-1

b)

Giúp mình các câu khác với ngo vinh thien 

please!!

=3 nha bn

KANZAKI MIZUKI GIẢI TRINH TỰ HỘ MÌNH VỚI

BẠN GIỎI TOÁN NHƯ VẬY GIÚP MÌNH VỚI