\(\dfrac{2}{5}\)+\(\dfrac{3}{5}\):\(\left(\dfrac{-9}{2}\right)\)+\(\dfrac{1}{2}\)

=\(\dfrac{2}{5}\)+\(\dfrac{3}{5}\).\(\left(\dfrac{-2}{9}\right)\)+\(\dfrac{1}{2}\)

=\(\dfrac{2}{5}\)+\(\left(\dfrac{-2}{15}\right)\)+\(\dfrac{1}{2}\)

=\(\dfrac{4}{15}\)+\(\dfrac{1}{2}\)

=\(\dfrac{23}{30}\)

23/30

Bạn cần viết đề bằng công thức toán để được hỗ trợ tốt hơn. Viết như thế kia rất khó đọc.

Lời giải:
\(A=\frac{-6(\frac{1}{7}-\frac{1}{13}+\frac{1}{29})}{9(\frac{1}{7}-\frac{1}{13}+\frac{1}{29})}=\frac{-6}{9}=\frac{-2}{3}\)

\(B=\frac{\frac{2}{15}-\frac{2}{21}+\frac{2}{39}}{\frac{5}{20}-\frac{5}{28}+\frac{5}{52}}=\frac{\frac{2}{3}(\frac{1}{5}-\frac{1}{7}+\frac{1}{13})}{\frac{5}{4}(\frac{1}{5}-\frac{1}{7}+\frac{1}{13})}=\frac{2}{3}: \frac{5}{4}=\frac{8}{15}\)

$A:B=\frac{-2}{3}: \frac{8}{15}=\frac{-5}{4}$

Mình nhầm xíu =))

\(\dfrac{1}{2}P+\dfrac{3}{4}\left(4-2P\right)=-4\)

\(\Rightarrow\dfrac{1}{2}.\left[P+\dfrac{3}{2}\left(4-2P\right)\right]=-4\)

\(\Rightarrow P+6-3P=-4:\dfrac{1}{2}=-8\)

\(\Rightarrow6-2P=-8\)

=> 2P = 14

=> P = 7

\(\dfrac{1}{2}P+\dfrac{3}{4}.\left(4-2P\right)=4\)

\(\Rightarrow\dfrac{1}{2}.\left[P+\dfrac{3}{2}\left(4-2P\right)\right]=4\)

\(\Rightarrow P+6-3P=4:\dfrac{1}{2}=8\)

\(\Rightarrow6-2P=8\)

\(\Rightarrow2P=6-8=-2\)

=> P = -1

\(X=10+12+14+...+98\)

\(X=\dfrac{98.45}{2}\)

\(X=2205\)

a.

\(3\dfrac{1}{3}+\dfrac{5}{6x}=3\dfrac{1}{2};đk...x\ne0\\ \Leftrightarrow\dfrac{5}{6x}=3\dfrac{1}{2}-3\dfrac{1}{3}\\ \Leftrightarrow\dfrac{5}{6x}=\dfrac{1}{6}\\ \Rightarrow x=5:\dfrac{1}{6}:6=5\)

b.

\(\dfrac{1}{2}-\dfrac{2}{3x}=\dfrac{7}{12}.đk...x\ne0\\ \Leftrightarrow\dfrac{2}{3x}=\dfrac{1}{2}-\dfrac{7}{12}\\ \Leftrightarrow\dfrac{2}{3x}=\dfrac{-1}{12}\\ \Rightarrow x=2:\dfrac{-1}{12}:3=-8\)

Đs....

a.

\(\dfrac{-2}{3}-\dfrac{1}{3}\left(2x-5\right)=\dfrac{3}{2}\\ \Leftrightarrow\dfrac{1}{3}\left(2x-5\right)=\dfrac{-2}{3}-\dfrac{3}{2}\\ \Leftrightarrow\dfrac{1}{3}\left(2x-5\right)=\dfrac{-13}{6}\\ \Leftrightarrow2x-5=\dfrac{-13}{6}:\dfrac{1}{3}=\dfrac{-13}{2}\\ \Leftrightarrow2x=\dfrac{-13}{2}+5=\dfrac{-3}{2}\\ \Rightarrow x=\dfrac{-3}{2}:2=\dfrac{-3}{4}\)

b.

\(\left(3x-1\right)\left(\dfrac{-1}{2}x+5\right)=0\\ \Rightarrow\left[{}\begin{matrix}3x-1=0\\\dfrac{-1}{2}x+5=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=10\end{matrix}\right.\)

   (6⁵ + 3.6² + 3³) : 13

= (7776 + 108 + 27) : 13

= 7911 : 13

= 7911/13 

A = | x + 1.5| = | x - 2.5|

A = | x + 5| = | x - 10|

x> 10 ⇔ x + 5 = x - 10 ⇔ 5 = -10 (loại)

x < - 5 ⇔ -x - 5 = -x + 10 (loại) 

-5< x < 10 ⇔ x + 5  = -x + 10 ⇔ 2x = 5 ⇔ x = 5/2

Sau bạn ghi đề rõ hơn nhé.

\(\dfrac{x-3}{-2}=\dfrac{18}{3-x};x\ne3\\ \Leftrightarrow\dfrac{3-x}{2}=\dfrac{18}{3-x}\\ \Leftrightarrow\left(3-x\right)^2=18.2=36=6^2\)

\(\Rightarrow\left[{}\begin{matrix}3-x=6\\3-x=-6\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-3\\x=9\end{matrix}\right.\)

Đs...

Em nên gõ công thức trực quan để được hỗ trợ tốt nhất