( y+1)+(y+2)+...+(y+37) = 999

(y+y+y+...+y+y) + (1+2+3+4+..+37) = 999

y. 37 + (1+(2+37)+(3+36)+...) = 999

y.37 + (1+ 39 + 39 + 39+ ...) = 999

y.37 + (1 + 39 . 18) = 999

y . 37 + (1+702) =999

y.37+ 703 = 999

y.37 = 999-703

y.37= 296

y= 296 : 37

y = 8

Vật y = 8

2: Tọa độ giao điểm là:

\(\left\{{}\begin{matrix}2x-1=x+1\\y=x+1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=2\\y=3\end{matrix}\right.\)

hiệu 2 số là:

2-1=1

nên y sẽ là 1

nên ta có tổng là:

37x37x2=2738

đáp số:2738

37 x y + 1 + 2 + 3+ ...+37 = 37 x y + (1 + 37) : 2 x 37

= 37 x (y + 19)

theo mik b vận dụng công thức khoảng cách cách đều ấy

\(12:y=\frac{3}{4}+\frac{4}{5}\)

\(12:y=\frac{15}{20}+\frac{16}{20}\)

\(12:y=\frac{31}{20}\)

       \(y=12:\frac{31}{20}\)

       \(y=12x\frac{20}{31}\)

       \(y=\frac{240}{31}\)

\(\frac{4}{5}xY=1\)

          \(y=1:\frac{4}{5}\)

          \(y=1x\frac{5}{4}\)

          \(y=\frac{5}{4}\)

\(\frac{37}{63}-y=\frac{1}{7}\)

              \(y=\frac{37}{63}-\frac{1}{7}\)

              \(y=\frac{37}{63}-\frac{9}{63}\)

              \(y=\frac{28}{63}\)

              \(y=\frac{4}{9}\)

\(y:\frac{3}{7}=\frac{3}{42}+\frac{5}{7}\)

\(y:\frac{3}{7}=\frac{3}{42}+\frac{30}{42}\)

\(y:\frac{3}{7}=\frac{33}{42}\)

\(y:\frac{3}{7}=\frac{11}{14}\)

        \(y=\frac{11}{14}x\frac{3}{7}\)

        \(y=\frac{33}{98}\)

\(12:y=\frac{3}{4}+\frac{4}{5}\)                                                                 \(\frac{37}{63}-y=\frac{1}{7}\)

\(12:y=\frac{31}{20}\)                                                                                       \(y=\frac{37}{63}-\frac{1}{7}\)

\(y=12:\frac{31}{20}\)                                                                                      \(y=\frac{4}{9}\)

\(y=\frac{240}{31}\)

\(\frac{4}{5}\cdot y=1\)                                                           \(y:\frac{3}{7}=\frac{3}{42}+\frac{5}{7}\)

\(y=1:\frac{4}{5}\)                                                           \(y:\frac{3}{7}=\frac{11}{14}\)

\(y=\frac{5}{4}\)                                                                \(y=\frac{11}{14}.\frac{3}{7}\)

                                                                                  \(y=\frac{33}{98}\)

\(12:y=\frac{3}{4}+\frac{4}{5}\)

\(=12;y=\frac{15}{20}+\frac{16}{20}\)

\(=12:y=\frac{31}{20}\)

\(=\frac{31}{20}\times12\)

\(=\frac{31}{20}\times\frac{12}{20}\)

\(=\frac{372}{400}\)

\(\dfrac{x}{3}=\dfrac{y}{4}=\dfrac{z}{5}\)

Áp dụng t.c của dãy tỉ só bằng nhau,ta có:

\(\dfrac{x}{3}=\dfrac{y}{4}=\dfrac{z}{5}=\dfrac{x+y}{3+4}=\dfrac{16}{7}\)

=>\(x=\dfrac{16}{7}.3=\dfrac{48}{7}\)

\(y=\dfrac{16}{7}.4=\dfrac{64}{7}\)

\(z=\dfrac{16}{7}.5=\dfrac{80}{7}\)

Vậy...

Các câu sau tương tự

ADTC dãy tỉ số bằng nhau ta cs

\(\frac{x}{2}=\frac{y}{3}=\frac{z}{4}=\frac{x^2+y^2}{2^2+3^2}=\frac{52}{13}=4\)

\(\Rightarrow\left\{{}\begin{matrix}\frac{x}{2}=4\\\frac{y}{3}=4\\\frac{z}{4}=4\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=8\\y=12\\z=16\end{matrix}\right.\)

d, \(\frac{x}{3}=\frac{y}{4}\) và \(x^3-y^3=-37\)

Có \(\frac{x}{3}=\frac{y}{4}\Rightarrow\frac{3x}{9}=\frac{3y}{12}\)

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

\(\frac{3x}{9}=\frac{3y}{12}=\frac{3x-3y}{9-12}=\frac{-37}{-3}=\frac{37}{3}\)

Do đó:

\(\frac{3x}{9}=\frac{37}{3}\Leftrightarrow\frac{x}{3}=\frac{37}{3}\Rightarrow x=\frac{3\times37}{3}=37\)

\(\frac{3y}{12}=\frac{37}{3}\Leftrightarrow\frac{y}{4}=\frac{37}{3}\Rightarrow y=\frac{4\times37}{3}=\frac{148}{3}\)

Vây x = 37 , y = \(\frac{148}{3}\)

\(\frac{x}{4}=\frac{y}{5}\Rightarrow\frac{x}{8}=\frac{y}{10}\) (1)

\(\frac{y}{2}=\frac{z}{3}\Rightarrow\frac{y}{10}=\frac{z}{15}\)(2)

Từ (1) và (2) \(\Rightarrow\frac{x}{8}=\frac{y}{10}=\frac{z}{15}\)

Áp dụng tính chất của dãy tỉ số bằng nhau ta được : 

\(\frac{x}{8}=\frac{y}{10}=\frac{z}{15}=\frac{x-y-z}{8-10-15}=\frac{37}{-17}\)

\(\Rightarrow\frac{x}{8}=\frac{37}{-17}\Rightarrow x=-\frac{296}{17}\)

\(\Rightarrow\frac{y}{10}=-\frac{37}{17}\Rightarrow y=-\frac{370}{17}\)

\(\Rightarrow\frac{z}{15}=-\frac{37}{17}\Rightarrow z=-\frac{555}{17}\)

Bài 4:

\(\dfrac{3}{4}+y:\dfrac{2}{5}=\dfrac{37}{16}\)

\(\Rightarrow y:\dfrac{2}{5}=\dfrac{37}{16}-\dfrac{3}{4}\)

\(\Rightarrow y:\dfrac{2}{5}=\dfrac{25}{16}\)

\(\Rightarrow y=\dfrac{2}{5}\cdot\dfrac{25}{16}\)

\(\Rightarrow y=\dfrac{5}{8}\)

________________

\(456+y:87=23987\)

\(\Rightarrow y:87=23987-456\)

\(\Rightarrow y:87=23531\)

\(\Rightarrow y=23531\cdot87\)

\(\Rightarrow y=2047197\)

a)\(\dfrac{4}{5}\times\dfrac{5}{8}:\dfrac{4}{5}\)

\(=\left(\dfrac{4}{5}:\dfrac{4}{5}\right)\times\dfrac{5}{8}\)

\(=1\times\dfrac{5}{8}=\dfrac{5}{8}\)

b)\(\dfrac{5}{6}+\left(\dfrac{1}{2}:\dfrac{3}{2}+\dfrac{4}{5}\right)\)

\(=\dfrac{5}{6}+\left(\dfrac{1}{3}+\dfrac{4}{5}\right)\)

\(=\dfrac{5}{6}+\dfrac{17}{15}\)

\(=\dfrac{59}{30}\)

Bài 2:

a) \(\dfrac{3}{4}+y:\dfrac{2}{5}=\dfrac{37}{16}\)

\(y:\dfrac{2}{5}=\dfrac{37}{16}-\dfrac{3}{4}\)

\(y:\dfrac{2}{5}=\dfrac{25}{16}\)

\(y=\dfrac{25}{16}\times\dfrac{2}{5}\)

\(y=\dfrac{5}{8}\)

b)\(456+y:87=23987\)

\(y:87=23987-456\)

\(y:87=23531\)

\(y=23531\times87\)

\(y=2047197\)

a) 4/5 x 5/8 : 4/5

= 5/8

b) 5/6 + ( 1/2 : 3/2 + 4/5)

= 5/6 + (1/3 + 4/5)

= 5/6 + 17/15

= 59/30

B4:

3/4 + y : 2/5 = 37/16

y : 2/5 = 25/16

y = 5/8.

456 + y : 87 = 23987

y : 87 = 23531

y = 2047197.