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

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

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

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

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

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

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

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

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

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

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 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

1}(y-25):4-120=0

(y-25):4=120

y-25=120 x 4

y-25=480

y=505

2}120-(x+25)x4=0

(x-25)x4=120

x-25=120:4

x-25=30

x=5

Ủng hộ mk nh các bạn ai k mk mk k lại

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

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

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

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

Nhanh giúp mình với cả nhà ơi