\(-2\dfrac{1}{5}=-\dfrac{11}{5}\)

\(\dfrac{110}{-50}=-\dfrac{11}{5}\)

\(\Rightarrow-2\dfrac{1}{5}=\dfrac{110}{-50}\)

ta có

x= \(-2\dfrac{1}{5}=\dfrac{-11}{5}\)

y=\(\dfrac{110}{-50}=\dfrac{-11}{5}\)

vì \(\dfrac{-11}{5}=\dfrac{-11}{5}\)nên x=y

\(\dfrac{x}{7}=\dfrac{y}{9}=\dfrac{z}{11}\)

Áp dụng tính chất của dãy tỉ sô bằng nhau ta có :

\(\dfrac{x}{7}=\dfrac{y}{9}=\dfrac{z}{11}=\dfrac{y-x}{9-7}=\dfrac{-1}{2}\)

\(\Rightarrow\left\{{}\begin{matrix}\dfrac{x}{7}=\dfrac{-1}{2}\\\dfrac{y}{9}=\dfrac{-1}{2}\\\dfrac{z}{11}=\dfrac{-1}{2}\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}x=\dfrac{-7}{2}\\y=\dfrac{-9}{2}\\z=\dfrac{-11}{2}\end{matrix}\right.\)

Ta có : \(\dfrac{x}{7}=\dfrac{y}{9}=\dfrac{z}{11}\)

Áp dụng tính chất dãy tỉ số bằng nhâu , ta có:

\(\dfrac{x}{7}=\dfrac{y}{9}=\dfrac{z}{11}=\dfrac{y-x}{9-7}=-\dfrac{1}{2}\\ \Rightarrow\left\{{}\begin{matrix}x=-\dfrac{1}{2}.7=-\dfrac{7}{2}\\y=-\dfrac{1}{2}.9=-\dfrac{9}{2}\\z=-\dfrac{1}{2}.11=-\dfrac{11}{2}\end{matrix}\right.\)

Vậy \(x=-\dfrac{7}{2}\); \(y=-\dfrac{9}{2}\); \(z=-\dfrac{11}{2}\)

Theo t/c dãy tỉ số bằng nhau ta có :

\(\dfrac{x}{7}=\dfrac{y}{8}=\dfrac{y-x}{8-7}=\dfrac{4}{1}=4\)

\(\Rightarrow\left\{{}\begin{matrix}\dfrac{x}{7}=4\Rightarrow x=7.4=28\\\dfrac{y}{8}=4\Rightarrow y=8.4=32\end{matrix}\right.\)

Vậy..............

Áp dụng tính chất dãy tỉ số bằng nhau ta có:

\(\dfrac{x}{7}=\dfrac{y}{8}=\dfrac{y-x}{8-7}=\dfrac{4}{1}=4\)

\(\Rightarrow\left\{{}\begin{matrix}\dfrac{x}{7}=4\Rightarrow x=28\\\dfrac{y}{8}=4\Rightarrow y=32\end{matrix}\right.\)

Vậy .............

Chúc bạn học tốt!

9/17.x+268/17.x-345/17.x=16

(9/17+268/17-345/17).x=16

-4.x=16

x=16:-4

x=-4

\(\dfrac{9}{17}x+15\dfrac{13}{17}x-20\dfrac{5}{17}x=16\)

\(\left(\dfrac{9}{17}+15\dfrac{13}{17}-20\dfrac{5}{17}\right)x=16\)

\(\left(\dfrac{9}{17}+\dfrac{268}{17}-\dfrac{345}{17}\right)x=16\)

\(x=16:\left(\dfrac{9}{17}+\dfrac{268}{17}-\dfrac{345}{17}\right)\)

\(x=-4\)

a: f(-2)-g(1/2)

\(=5\left(-2\right)-3+4\cdot\dfrac{1}{2}-1\)

\(=-10-4+2=-10-2=-12\)

b: \(2\cdot f^2\left(-3\right)-3\cdot g^2\left(-2\right)\)

\(=2\cdot\left[5\cdot\left(-3\right)-3\right]^2-3\cdot\left[\left(-4\right)\left(-2\right)+1\right]^2\)

\(=2\cdot\left(-18\right)^2-3\cdot9^2\)

\(=648-3\cdot81=405\)

1/10

x = \(\dfrac{2}{20}=\dfrac{1}{10}\)

\(1\dfrac{13}{15}\cdot0,75-\left[\dfrac{11}{20}+25\%\right]\div\dfrac{7}{5}\\ =\dfrac{28}{15}\cdot0,75-\dfrac{4}{5}\cdot\dfrac{5}{7}\\ =\dfrac{7}{5}-\dfrac{4}{7}=\dfrac{29}{35}\)

a)\(\left|-0.75\right|+\dfrac{1}{4}-2\dfrac{1}{2}\)

=0.75+0.25-2.5

=1-2.5=-1.5

b)\(15.\dfrac{1}{5}:\left(\dfrac{-5}{7}\right)-2\dfrac{1}{5}.\left(\dfrac{-7}{5}\right)\)

=3.(-1.4)+3.08

=-4.2+3.08=-1.12

c)\(\dfrac{5}{17}+\dfrac{2}{3}-\dfrac{20}{12}+\dfrac{7}{9}+\dfrac{12}{17}\)

=\(\dfrac{49}{51}-\dfrac{5}{3}+\dfrac{7}{9}+\dfrac{12}{17}\)

=\(\dfrac{-12}{17}+\dfrac{7}{9}+\dfrac{12}{17}\)

=\(\dfrac{11}{153}+\dfrac{12}{17}\)

=\(\dfrac{7}{9}\)

d)\(\dfrac{5}{15}+\dfrac{14}{25}-\dfrac{12}{9}+\dfrac{2}{7}+\dfrac{11}{25}\)

=\(\dfrac{67}{75}-\dfrac{4}{3}+\dfrac{2}{7}+\dfrac{11}{25}\)

=-0.44+\(\dfrac{127}{175}\)

=\(\dfrac{2}{7}\)

\(\dfrac{17}{20}\) x \(\dfrac{27}{13}\) + \(\dfrac{27}{13}\)  x \(\dfrac{3}{20}\)

= (\(\dfrac{17}{20}\)  + \(\dfrac{3}{20}\)) x \(\dfrac{27}{13}\)

= 1 x \(\dfrac{27}{13}\)

=\(\dfrac{27}{13}\)

Tick cho mik nha