\(\frac{-19}{20}\)

=\(\frac{-21}{20}\)

hok tốt

nhớ tkkk nhìu zô

\(\Rightarrow\frac{x-3}{3}=\frac{y-2}{2}\)

áp dụng tc của dãy tỉ số bằng nhau ta có:

\(\frac{x-3}{3}=\frac{y-2}{2}=\frac{\left(x-3\right)-\left(y-2\right)}{3-2}=3\)

\(\Rightarrow\hept{\begin{cases}x=3.3+3=12\\y=3.2+2=8\end{cases}}\)

\(\frac{x-3}{y-2}=\frac{3}{2}\)

\(\text{Ta có : }x-y=4\Leftrightarrow x=4+y\)

\(\text{Thay vào biểu thức ta có :}\)

\(\frac{y+4-3}{y-2}=\frac{3}{2}\)

\(\Leftrightarrow\frac{y+1}{y-2}=\frac{3}{2}\)

\(\Leftrightarrow\left(y+1\right).2=\left(y-2\right).3\)

\(\Leftrightarrow2y+2=3y-6\)

\(\Leftrightarrow2y-3y=-2-6\)

\(\Leftrightarrow-1y=-8\)

\(\Leftrightarrow y=8\)

\(\text{Vì x = y + 4}\)

\(\Rightarrow x=12\)

\(\left(\frac{7}{2}-x\right).\frac{5}{4}=\frac{-21}{20}\)

\(\frac{7}{2}-x=\frac{-21}{25}\)

\(x=\frac{217}{50}\)

Vậy ...

\(a,\left[3\frac{1}{2}-x\right]\cdot1\frac{1}{4}=-1\frac{1}{20}\)

\(\Rightarrow\left[3\frac{1}{2}-x\right]\cdot\frac{5}{4}=-\frac{21}{20}\)

\(\Rightarrow\left[3\frac{1}{2}-x\right]=-\frac{21}{20}:\frac{5}{4}\)

\(\Rightarrow\left[3\frac{1}{2}-x\right]=-\frac{21}{20}\cdot\frac{4}{5}\)

\(\Rightarrow\left[3\frac{1}{2}-x\right]=-\frac{21}{25}\)

Bỏ dấu ngoặc đó rồi ghi như cũ rồi sau đó tìm x nhé :v

58.75+58.50-58.5

=58.(75+50-5)

=58.120

=6960

_Hok tốt_

\(=58.\left(75+50-5\right)\)

\(=58.120\)

\(=6960\)

1) The square in Ha Noi is bigger than the square in Hoi An

2)Shall we go oat anh have a drink

1. The square in Hoi An is smaller than the square in Hanoi.

=> The square in Ha Noi is bigger than the square in Hoi An.

2. Let's go out and have a drink.

=> Shall we go out and have a drink?

3. Can you tell me the way to the bus stop?

=> How can I get to the way to the bus stop?

4. Our neighborhood is quieter than you neighorhood.

=> Your neighborhood is noisier than our neighborhood.

5. This house is more modern than that house.

=> That house is more historic than this house.

Để ( x + 1 ) ( 2y - 5 ) = 143 \(\in N\)thì x + 1 \(\in N\)và 2y - 5 \(\in N\)

Mà 143 = 11.13 ; 143 = 143.1

\(\Rightarrow\)Ta có bảng sau :

Vậy ta tìm được 4 cặp số ( x;y ) thỏa mãn đề bài là : ( 10;9 ) ; ( 12;8 ) ; ( 142;3 ) ; ( 0;74 )

Nhận xét:

143 = 1.143 = 11.13

Vậy (x;y)\(\in\){ (0:74) ; (142;3) ; (10;9) ; (12;8) }

S = 1 - 3 + 3^2 - 3^3 + ... + 3^98 - 3^99

S = (1 - 3 + 3^2 - 3^3) + ... + (3^96 - 3^97 + 3^98 - 3^99 )

S = (-20) + (-20) +...+ (-20)   (24 số -20)

S = (-20).24 chia hết cho -20

=> đpcm

Câu hỏi của Nguyễn Dương - Toán lớp 6 - Học toán với OnlineMath

Bạn tham khảo.

\(\frac{3}{4}-\frac{1}{4}x-1=40\%\times\frac{-5}{3}\)

\(\Leftrightarrow\frac{1}{4}\left(3-x\right)-1=\frac{40}{100}\times\frac{-5}{3}\)

\(\Leftrightarrow\frac{1}{4}\left(3-x\right)-1=\frac{2}{5}\times\frac{-5}{3}\)

\(\Leftrightarrow\frac{1}{4}\left(3-x\right)-\frac{15}{15}=\frac{-10}{15}\)

\(\Leftrightarrow\frac{1}{4}\left(3-x\right)=\frac{-10}{15}+\frac{15}{15}\)

\(\Leftrightarrow\frac{1}{4}\left(3-x\right)=\frac{5}{15}\)

\(\Leftrightarrow3-x=\frac{5}{15}\div\frac{1}{4}\)

\(\Leftrightarrow3-x=\frac{5}{15}\times4\)

\(\Leftrightarrow\frac{45}{15}-x=\frac{20}{15}\)

\(\Leftrightarrow x=\frac{45}{15}-\frac{20}{15}\)

\(\Leftrightarrow x=\frac{25}{15}=\frac{5}{3}\)

\(n+2\)là ước của \(111\)là:\(\left(1;3;37;111\right)\)

\(\Rightarrow n\in\left\{\pm1;35;109\right\}\)

\(n-2\)là bội\(11\)là\(\left(0,11,22,33;...\right)\)

\(\Rightarrow n\in\left\{2;24;35;...\right\}\)

Vì n dương nên n=35

n = 35 nhé bạn !

\(\text{a) }\left(5x+1\right)\left(y-1\right)=4\)

\(\Leftrightarrow5x+1,y-1\inƯ\left(4\right)\)

\(\Leftrightarrow5x+1,y-1\in\left\{\pm1;\pm2;\pm4\right\}\)

Ta có bảng :

\(\text{b) }5xy-5x+y=5\)

\(\Leftrightarrow\left(5xy+y\right)-5x=5\)

\(\Leftrightarrow y\left(5x+1\right)-\left(5x+1\right)-1=5-1\)

\(\Leftrightarrow y\left(5x+1\right)-\left(5x+1\right)-1=4\)

\(\Leftrightarrow\left(y-1\right).\left(5x+1\right)=4\)

\(\Leftrightarrow y-1,5x+1\inƯ\left(4\right)\)

\(\Leftrightarrow y-1,5x+1\in\left\{\pm1;\pm2;\pm4\right\}\)

Ta có bảng :