\(\left(\frac{1}{25.26}+\frac{1}{26.27}+...+\frac{1}{29.30}\right)\cdot150+1,03\div\left[1,03\cdot\left(y-1\right)\right]\text{ }=22\)

\(\Rightarrow\left(\frac{1}{25}-\frac{1}{26}+\frac{1}{26}-\frac{1}{27}+...+\frac{1}{29}-\frac{1}{30}\right)\cdot150+1,03\div\left[1,03\cdot\left(y-1\right)\right]=22\)

\(\Rightarrow\left(\frac{1}{25}-\frac{1}{30}\right)\cdot150+1,03\div\left[1,03\cdot\left(y-1\right)\right]=22\)

\(\Rightarrow\frac{1}{150}\cdot150+1,03\div\left[1,03\left(y-1\right)\right]=22\)

\(\Rightarrow1+1,03\div\left[1,03\left(y-1\right)\right]=22\)

\(\Rightarrow1,03\left(y-1\right)=1,03\div\left(22-1\right)\)

\(\Rightarrow1,03y-1,03=1,03\div21\)

\(\Rightarrow1,03y=\frac{103}{2100}+1,03\)

\(\Rightarrow1,03y=\frac{1133}{1050}\)

\(\Rightarrow y=\frac{1133}{1050}\div\frac{103}{100}=\frac{1133}{1050}\cdot\frac{100}{103}=\frac{22}{21}\)

Vậy y = \(\frac{22}{21}\)

Dấu " . " là dấu nhân nhé 

\(\left(\frac{1}{25\times26}+\cdot\cdot\cdot+\frac{1}{29\times30}\right)\times150+1\frac{3}{100}:[1\frac{3}{100}\times(y-1)]=22\)

\(\Rightarrow\left(\frac{1}{25}-\frac{1}{26}+\cdot\cdot\cdot+\frac{1}{29}-\frac{1}{30}\right)\times150:\left(y+1\right)=22\)

\(\Rightarrow\left(\frac{1}{25}-\frac{1}{30}\right)\times150:\left(y+1\right)=22\)

\(\Rightarrow\frac{1}{150}\times150:\left(y+1\right)=22\)

\(\Rightarrow1:\left(y+1\right)=22\)

\(\Rightarrow y+1=\frac{1}{22}\)

\(\Rightarrow y=\frac{1}{22}-1=\frac{-21}{22}\)

( 1/25 - 1/30 ) x 150 + 1,03 : 1,03 x ( x - 1 ) = 3 ( 1/150 x 150 + 1 x ( x - 1 ) = 3 1 + ( x - 1 ) = 3 x - 1 = 3 - 1 = 2 x = 1 + 2 x = 3

[ 1/ 25 x 26 + 1/26x27+....+ 1/29x30] x 150 + 103; 1,03 x ( x -1 ) =22

[ 1/25x26 + 1/26x27 + 1/27x28 + 1/28x29 + 1/29x30] x 150 + 103;1,03 x (x-1)=22

[ 1/650 + 1/702 + 1/756 + 1/812 + 1/870] x 150 + 103 ; 1,03 x (x-1) =22

1>y-25=120.4

y-25=480

y=505

2>4 nhân (x+25)=120

x+25=30

x=5

1) ( y-25):4 - 120 = 0                                               2) 120 - ( x+25 )x4 = 0

( y-25 ):4 = 0+120                                                       (x+25) x4 =120-0     

( y-25):4 =120                                                             (x+25) x4 =120

( y-25)=120x4                                                             (x+25)=120:4

y-25=480                                                                    x+25=30

y=480+25                                                                        x=30-25

y=505                                                                              x=5

k mk nha

\(\dfrac{1}{1\times2}+\dfrac{1}{2\times3}+\dfrac{1}{3\times4}+....+\dfrac{1}{24\times25}\)

\(=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{24}-\dfrac{1}{25}\)

\(=1-\dfrac{1}{25}\)

\(=\dfrac{24}{25}\)

Nhanh giúp mình với cả nhà ơi

a: \(\frac{52}{17}>\frac{51}{17}=3\)

\(3=\frac{121}{41}>\frac{120}{41}\)

Do đó: \(\frac{52}{17}>\frac{120}{41}\)

b: \(\frac34+\frac14:\left(\frac{7}{12}-\frac16\right)\)

\(=\frac34+\frac14:\left(\frac{7}{12}-\frac{2}{12}\right)\)

\(=\frac34+\frac14:\frac{5}{12}\)

\(=\frac34+\frac14\times\frac{12}{5}=\frac34+\frac35=\frac{15}{20}+\frac{12}{20}=\frac{27}{20}\)

c: \(372,463\cdot998+744,926\)

\(=372,463\cdot998+372,463\cdot2\)

\(=372,463\times\left(998+2\right)=372,463\times1000=372463\)

d: Số số hạng trong dãy số 2;4;6;...;100 là:

\(\left(100-2\right):2+1=98:2+1=49+1=50\) (số)

\(2-4+6-8+10-12+\cdots+98-100+102\)

\(=\left(2-4\right)+\left(6-8\right)+\cdots+\left(98-100\right)+102\)

=(-2)+(-2)+...+(-2)+102

\(=-2\cdot\frac{50}{2}+102=-50+102=52\)

e: (y+112)-113=79

=>y+112-113=79

=>y-1=79

=>y=79+1=80

f: \(\frac34-y=\frac12\)

=>\(y=\frac34-\frac12=\frac14\)

g: \(\left(\frac45-2\times y\right)+\frac16=\frac56\)

=>\(\frac45-2\times y=\frac56-\frac16=\frac46=\frac23\)

=>\(2\times y=\frac45-\frac23=\frac{12}{15}-\frac{10}{15}=\frac{2}{15}\)

=>\(y=\frac{2}{15}:2=\frac{1}{15}\)

h: (y+1)+(y+2)+...+(y+50)=1750

=>50y+(1+2+...+50)=1750

=>\(50y+50\times\frac{51}{2}=1750\)

=>50y+1275=1750

=>50y=1750-1275=475

=>\(y=\frac{475}{50}=9,5\)