C1:997                             C6:1;2

C2:-13                              C7:50

C3:-4;1;27                         C8:1

C4:0                                 C9:14

C5:20;50                           C10:3;1

toán lớp 6 chứ lớp 7 gì

\(\frac{-11}{12}\)  .x+0.25 = \(\frac{5}{6}\)

\(\frac{-11}{12}\) .x+ \(\frac{1}{4}\)= \(\frac{5}{6}\)

\(\frac{-11}{12}\).x            =\(\frac{5}{6}\)- \(\frac{1}{4}\)

\(\frac{-11}{12}\).x            = \(\frac{7}{10}\)

                 x            = \(\frac{7}{10}\)- \(\frac{-11}{12}\)

                  x            = \(\frac{47}{60}\)

k cho mik nha,chúc bn học tốt

\(\frac{-11}{12}\cdot x+0,25=\frac{5}{6}\)

\(\Rightarrow\frac{-11}{12}\cdot x+\frac{1}{4}=\frac{5}{6}\)

\(\Rightarrow\frac{-11}{12}\cdot x=\frac{5}{6}-\frac{1}{4}\)

\(\Rightarrow\frac{-11}{12}\cdot x=\frac{7}{12}\)

\(\Rightarrow x=\frac{7}{12}:\frac{-11}{12}\)

\(\Rightarrow x=\frac{7}{-11}\)

vay___

\(-\dfrac{11}{12}\cdot x+0,25=\dfrac{5}{6}\\ -\dfrac{11}{12}\cdot x=\dfrac{5}{6}-\dfrac{1}{4}\\ -\dfrac{11}{12}\cdot x=\dfrac{7}{12}\\ x=\dfrac{7}{12}:-\dfrac{11}{12}\\ x=-\dfrac{7}{11}\\ Vậyx=-\dfrac{7}{11}\)

Sorry mink ko biet lm bài lớp 7 mink mới học có lớp 5 thôi à . Mong là sẽ có người lm đc giúp bn .

Cho mình hỏi: 1), 2) thuộc bài mấy trong toán lớp 78 vậy bạn.

a: \(=\left(\dfrac{11}{17}+\dfrac{6}{17}\right)+\left(-\dfrac{5}{13}-\dfrac{8}{13}\right)+\dfrac{11}{25}\)

=11/25+1-1=11/25

b: \(=\sqrt{36\cdot\dfrac{1}{4}}+11=9+11=20\)

c: \(=\left(0.25\right)^8\cdot4^8=\left(0.25\cdot4\right)^8=1\)

d: \(=2.8\left(-6.5-3.5\right)=-10\cdot2.8=-28\)

Ta thấy: \(\begin{cases}\left(2x+1\right)^2\ge0\\\left|y+1,2\right|\ge0\end{cases}\)

\(\Rightarrow\left(2x+1\right)^2+\left|y+1,2\right|\ge0\)

Để \(\left(2x+1\right)^2+\left|y+1,2\right|=0\)

\(\Rightarrow\begin{cases}\left(2x+1\right)^2=0\\\left|y+1,2\right|=0\end{cases}\)\(\Rightarrow\begin{cases}2x+1=0\\y+1,2=0\end{cases}\)

\(\Rightarrow\begin{cases}2x=-1\\y=-1,2\end{cases}\)\(\Rightarrow\begin{cases}x=-\frac{1}{2}\\y=-1,2\end{cases}\)

\(\Rightarrow x+y=-\frac{1}{2}+\left(-1,2\right)=-1,7\)

bài tập violympic bn nên tự lm

a) X>Y

b)X<Y

c)x<Y

Bài 1:

a) Ta có:

\(3,2\cdot x+\left(-1,2\right)\cdot x+2,7=-4,9\)

\(\Rightarrow\left[3,2+\left(-1,2\right)\right]\cdot x=\left(-4,9\right)-2,7\)

\(\Rightarrow2x=-7,6\)

\(\Rightarrow x=\left(-7,6\right):2\)

\(\Rightarrow x=-3,8\)

Vậy \(x=-3,8\)

b) Ta có:

-5,6.x+2,9.x-3,86=-9,8

=>[(-5,6)+2,9].x=(-9,8)+3,86

=>(-2,7).x=-5,94

=>x=(-5,94):(-2,7)

=>x=2,3

Vậy x=2,2

vậy còn bài 2 đâu bạn

\(a,\frac{15^3.\left(-5\right)^4}{\left(-3\right)^5.5^6}\)\(=\frac{3^3.5^3}{\left(-3\right)^5.5^2}\)\(=-\frac{5}{\left(3\right)^2}=-\frac{5}{9}\)

\(b,\frac{6^3.2.\left(-3\right)^2}{\left(-2\right)^9.3^7}\)\(=-\frac{6^3}{2^8.3^5}\)\(=-\frac{2^3.3^3}{2^8.3^5}\)\(=-\frac{1}{2^5.3^2}=-\frac{1}{288}\)

\(c,\frac{3^6.7^2-3^7.7}{3^7.21}\)\(=\frac{3^6.7\left(7-3\right)}{3^7.21}\)\(=\frac{3^6.7.4}{3^7.7.3}\)\(=\frac{4}{3.3}=\frac{4}{9}\)

\(a,\left(x-1,2\right)^2=4\)

\(\Rightarrow x-1,2=2\)

\(\Rightarrow x=3,2\)

\(b,\left(x+1\right)^3=-125\)

\(\Rightarrow\left(x+1\right)^3=\left(-5\right)^3\)

\(\Rightarrow x+1=-5\Rightarrow x=-6\)

\(c,\left(x-5\right)^3=2^6\)

\(\Rightarrow\left(x-5\right)^3=4^3\)

\(\Rightarrow x-5=4\Rightarrow x=9\)

\(d,\left(2x+1\right)^{x+1}=5^{x+1}\)

\(\Rightarrow2x+1=5\Rightarrow x=2\)

= - 1,7

-1,7