Ta có:

37.41+37.63-63.37+63.41

=41(37+63)

=41.100

=4100

Ta có:

20-5x=15+6x-6

<=>20-5x-15-6x+6=0

<=>11-11x=0

<=>11x=11

<=>x=1

Vậy x=1

Đề sai nên mình xin phép sửa:

Tìm x,y,z biết: \(\frac{x}{2}=\frac{y}{-3}=\frac{z}{4}\) và \(x-5y-3z=10\)

Bài làm:

Áp dụng t/c dãy tỉ số bằng nhau ta có:

\(\frac{x}{2}=\frac{y}{-3}=\frac{z}{4}=\frac{x-5y-3z}{2+15-12}=\frac{10}{5}=2\)

\(\Rightarrow\hept{\begin{cases}x=2\cdot2=4\\y=\left(-3\right)\cdot2=-6\\z=4\cdot2=8\end{cases}}\)

Vậy (x;y;z) = (4;-6;8)

thay X = Y nha ko thì nhầm nhân với x

ĐẦU TIÊN TA LÀM :

Y x 2/3 = 37/12 + 1/4 = 40/12 = 10/3

THỨ HAI TÌM Y :

Y x 2/3 = 10/3                            Y = 10/3 : 2/3 = 30/6 = 5 

=======>NHỚ K MÌNH , CHÚC HỌC GIỎI <=======

X x 2/3 - 1/4 = 37/12

=> X x 2/3 = 37/12 + 1/4

=> X x 2/3 = 40/12 = 10/3

=> X = 10/3 : 2/3

=> X = 30/6 = 5

vậy x = 5

k cho chị nhan, chị học lớp 7 rồi nên kết qả ko sai đâu

\(x\cdot\frac{2}{3}-\frac{1}{4}=\frac{37}{12}\)

\(x\cdot\frac{2}{3}=\frac{37}{12}+\frac{1}{4}\)

\(x\cdot\frac{2}{3}=\frac{10}{3}\)

\(x=\frac{10}{3}:\frac{2}{3}\)

\(x=5\)

a) => 14 - x + 100 = 101

=> 14 - x = 1

=> x = 13

b) => 5x + (1 + 2 + 3 + 4 + 5) = 355

=> 5x + 15 = 355

=> 5x = 340

=> x = 68

\(b.\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+\left(x+4\right)+\left(x+5\right)=355\)

\(\left(x.5\right)+\left(1+2+3+4+5\right)=355\)

\(\left(x.5\right)+15=355\)

\(x.5=355-15\)

\(x.5=340\)

\(x=340:5\)

\(x=68\)

a) \(3737:\left(14-x+100\right)=37\)

\(\Rightarrow14-x+100=3737:37\)

\(\Rightarrow14-x+100=101\)

\(\Rightarrow14-x=101-100\)

\(\Rightarrow14-x=1\)

\(\Rightarrow x=14-1\)

\(\Rightarrow x=13\)

Vậy \(x=13\)

b) \(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+\left(x+4\right)+\left(x+5\right)=355\)

\(\Rightarrow\left(x+x+x+x+x\right)+\left(1+2+3+4+5\right)=355\)

\(\Rightarrow5x+15=355\)

\(\Rightarrow5x=355-15\)

\(\Rightarrow5x=340\)

\(\Rightarrow x=340:5\)

\(\Rightarrow x=68\)

Vậy \(x=68\)

1) x = 4/5 - 1/3

x = 7/15

2) 5/3.x=1/21

x=1/35

3) -12/13.x = 1/13

x=-1/12

7) th1: x-1=2/3

x = 5/3

Th2: x - 1 = -2/3

x=1/3

 1) 9-25=(7-x)-(25+7)

(7-x)-(25+7)=9-25

(7-x)-(25+7)=-16

(7-x)-32=-16

7-x=-16+32

7-x=16

x=7-16

x=-9

2) (27-514) -(486-73)+x=7

 (27-514) -(486-73)+x=7

-487-413+x=7

-1011+x=7

x=7-(-1011)

x=7+1011

x=1018

3) 25+5+37-25+6-29-x=37

 25+5+37-25+6-29-x=37

67-25+6-29-x=37

42+6-29-x=37

48-29-x=37

19-x=37

x=19-37

x=-18

4) 14+(-12)+x =10-/-15/+ /-3/

14+(-12)+x =10-15+3

14+(-12)+x =-5+3

14+(-12)+x =-2

2+x=-2

x=-2-2

x=-4

1) - 9

2) 1018 

3) -18 

4) -4

tick nha

ta co tu suy nghi 

chuẩn CMNR ;+

Cách 1:

 A = \(\frac{2}{1.2.3}\)+ \(\frac{2}{2.3.4}\)+ \(\frac{2}{3.4.5}\)+ .... + \(\frac{2}{36.37.38}\)+ \(\frac{2}{37.38.39}\)

A = \(\frac{3-1}{1.2.3}\)+ \(\frac{4-2}{2.3.4}\)+ \(\frac{5-3}{3.4.5}\)+ ... + \(\frac{38-36}{36.37.38}\)+ \(\frac{39-37}{37.38.39}\)

A = ( \(\frac{3}{1.2.3}\)- \(\frac{1}{1.2.3}\) )+ ( \(\frac{4}{2.3.4}\)-\(\frac{2}{2.3.4}\)) + ... + (\(\frac{38}{36.37.38}\)- \(\frac{36}{36.37.38}\)) + (\(\frac{39}{37.38.39}\)- \(\frac{37}{37.38.39}\))

A = ( \(\frac{1}{1.2}\)- \(\frac{1}{2.3}\)) + (\(\frac{1}{2.3}\) -\(\frac{1}{3.4}\) ) + ... + ( \(\frac{1}{36.37}\)- \(\frac{1}{37.38}\)) + ( \(\frac{1}{37.38}\)- \(\frac{1}{38.39}\))

A = \(\frac{1}{1.2}\)+ (-\(\frac{1}{2.3}\)+ \(\frac{1}{2.3}\)) + (-\(\frac{1}{3.4}\)+ \(\frac{1}{3.4}\)) + ..... + ( -\(\frac{1}{37.38}\)+\(\frac{1}{37.38}\)) - \(\frac{1}{38.39}\)

A = \(\frac{1}{1.2}\)+ 0 + 0 + 0 +... + 0 - \(\frac{1}{38.39}\)

A = \(\frac{1}{1.2}\)- \(\frac{1}{38.39}\)= \(\frac{741}{1482}\)- \(\frac{1}{1482}\)= \(\frac{740}{1482}\)=\(\frac{370}{741}\)