\(A=\frac{3^2}{1.4}+\frac{3^2}{4.7}+\frac{3^2}{7.10}+...+\frac{3^2}{97.100}\)

\(\Rightarrow A=3\left(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{97.100}\right)\)

\(\Rightarrow A=3\left(\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{97}-\frac{1}{100}\right)\)

\(\Rightarrow A=3.\left(1-\frac{1}{100}\right)\)

\(\Rightarrow A=3.\frac{99}{100}\)

\(\Rightarrow A=\frac{297}{100}\)

Vậy \(A=\frac{297}{100}\)

wow hay thiệt mình làm giống kết quả nhưng khác cách giải thanks bạn nhìu nha

ta có : 2(x-3)=3(y-2)

2x-6=3y-6

2x=3y hay 2x-2y=y

2(x-y)=y

y=2.4=8;x=2.8:3=6

Bạn ơi ,sai rồi hay sao ý!!

38.x-x.12-x.16=40

<=> x(38-12-16)=40

<=> x.10=40

<=>x =4

\(Ta có: 38.x-x.12-x.16=40 \)

     \(\Rightarrow (38-12-16).x=40\)

     \(\Rightarrow 10.x=40\)

     \(\Rightarrow x=40:10\)

     \(\Rightarrow x=4\)

HOK TỐT...

( 5/17+-2/17)+(-9/15+-2/5)

=(5/17+-2/17)+(-9/15+-6/15)

=3/17+-15/15

=3/17+(-1)

=(-14)/17

k mình nha! căm ơn bạn!!!!

= (5/17-2/17) - (9/15+2/5)

= 3/17 - 1

= -14/17

Tk mk nha

tớ kb rùi tk đi

tớ gửi rùi tk hộ mk đi

hay quá

999

\(\frac{1}{24\cdot25}+\frac{1}{25\cdot26}+...+\frac{1}{29\cdot30}\)

\(=\frac{1}{24}-\frac{1}{25}+\frac{1}{25}-\frac{1}{26}+...+\frac{1}{29}-\frac{1}{30}\)

\(=\frac{1}{24}-\frac{1}{30}\)

\(=\frac{1}{120.}\)

\(\frac{1}{24.25}+\frac{1}{25.26}+...+\frac{1}{29.30}\)

\(=\frac{1}{24}-\frac{1}{25}+\frac{1}{25}-\frac{1}{26}+...+\frac{1}{29}-\frac{1}{30}\)

\(=\frac{1}{24}-\frac{1}{30}\)

\(=\frac{1}{120}\)

Ủng hộ mk nha ^_-

\(\frac{18}{37}+\frac{8}{24}+\frac{19}{37}-1\frac{23}{24}+\frac{2}{3}\\ =\left(\frac{18}{37}+\frac{19}{37}\right)+\left(\frac{1}{3}+\frac{2}{3}\right)-1\frac{23}{24}\\ =1+1-1\frac{23}{24}\\ =2-1\frac{23}{24}\\ =\frac{1}{24}\)

\(\frac{18}{37}+\frac{8}{24}+\frac{19}{37}-1\frac{23}{24}+\frac{2}{3}\)

= \(\frac{18}{37}+\frac{8}{24}+\frac{19}{37}-\frac{47}{24}+\frac{16}{24}\)

= \(\left(\frac{18}{37}+\frac{19}{37}\right)+\left(\frac{8}{24}-\frac{47}{24}+\frac{16}{24}\right)\)

= \(1+\frac{-23}{24}\)

= \(\frac{24}{24}+\frac{-23}{24}\)

= \(\frac{1}{24}\)