Đề là j

để là quy đồng mẫu số

à nhầm đề

địt con mẹ mày lên

\(\dfrac{1}{3}\)-\(\dfrac{2}{15}\)+\(\dfrac{14}{15}\)=\(\dfrac{3}{15}\)-\(\dfrac{2}{15}\)+\(\dfrac{14}{15}\)

=\(\dfrac{13}{15}\)

\(\dfrac{3}{5}\)+4-\(\dfrac{6}{7}\)=\(\dfrac{3}{5}\)+\(\dfrac{20}{5}\)-\(\dfrac{6}{7}\)=\(\dfrac{23}{5}\)-\(\dfrac{6}{7}\)=\(\dfrac{161}{35}\)-\(\dfrac{30}{35}\)=\(\dfrac{131}{35}\)

98

98

98

A

A

A

\(\dfrac{1}{2}=\dfrac{6}{12};\dfrac{2}{3}=\dfrac{8}{12};\dfrac{7}{12}=\dfrac{7}{12}\)

Chắc là quy đồng nhỉ :)

\(\dfrac{1\times6}{2\times6}=\dfrac{6}{12};\dfrac{2\times4}{3\times4}=\dfrac{8}{12};\dfrac{7}{12}\)

6/12

8/12

7/12 

giúp mình với

a. x + 3/10= 25/8

x = 25/8-3/10

x = 113/40

b. x/35 = 4/5-5/7

x/35 = 3/35

vậy x=3

\(x+\dfrac{3}{10}=4-\dfrac{7}{8}\)

\(x+\dfrac{3}{10}=\dfrac{25}{8}\)

        \(x=\dfrac{25}{8}-\dfrac{3}{10}\)

       \(x=\dfrac{113}{40}\)

\(\dfrac{5}{7}+\dfrac{x}{35}=\dfrac{4}{5}\)

        \(\dfrac{x}{35}=\dfrac{4}{5}-\dfrac{5}{7}\)

        \(\dfrac{x}{35}=\dfrac{3}{35}\)

    =>x=3

( 2007 − 2005 ) + ( 2003 − 2001 ) +...+ ( 7 − 5 ) + ( 3 − 1 )

= 2 + 2 +.....+ 2 + 2

Số hạng của dãy trên là: ( 2007 - 1 ) : 2 + 1 = 1004 ( số hạng ) và có 502 chữ số 2

⇒Tổng là: 2 x 502 = 1004

(2007−005)+(2003−2001)+...+(7−5)+(3−1)=2+2+.....+2+2Số hạng của dãy trên là:(2007−1):2+1=1004(số hạng) và có 502 chữ số 2⇒Tổng là:2*502=1004

a: =152,3+7,7+2021,19-2021,19

=160

b: =7/15*3/14*20/13

\(=\dfrac{7}{14}\cdot\dfrac{3}{15}\cdot\dfrac{20}{13}=\dfrac{1}{2}\cdot\dfrac{1}{5}\cdot\dfrac{20}{13}=\dfrac{2}{13}\)

c: \(=\dfrac{7}{4}\left(\dfrac{13}{12}-\dfrac{10}{12}\right)+\dfrac{5}{6}=\dfrac{7}{16}+\dfrac{5}{6}=\dfrac{61}{48}\)

giải chi tiết hộ mình nhé

\(3\times\dfrac{7}{10}+\dfrac{7}{10}\times5+2\times\dfrac{7}{10}\)

\(=\dfrac{7}{10}\times\left(3+5+2\right)\)

\(=\dfrac{7}{10}\times10\)

\(=\dfrac{70}{10}=7\)

giúp mình đi T.T