Tàu là trùm

a: Cách 1: \(\left(\frac58-\frac72\right):\frac65\)

\(=\left(\frac58-\frac{28}{8}\right):\frac65\)

\(=-\frac{23}{8}\cdot\frac56=\frac{-115}{48}\)

Cách 2: \(\left(\frac58-\frac72\right):\frac65\)

\(=\left(\frac58-\frac72\right)\cdot\frac56\)

\(=\frac58\cdot\frac56-\frac72\cdot\frac56\)

\(=\frac{25}{48}-\frac{35}{12}\)
\(=\frac{25}{48}-\frac{140}{48}=\frac{-115}{48}\)

b: Cách 1: \(\frac47\left(\frac85+\frac53\right)\)

\(=\frac47\cdot\frac85+\frac47\cdot\frac53\)

\(=\frac{32}{35}+\frac{20}{21}\)

\(=\frac{96}{105}+\frac{100}{105}=\frac{196}{105}=\frac{28}{15}\)

Cách 2: \(\frac47\left(\frac85+\frac53\right)\)

\(=\frac47\left(\frac{24}{15}+\frac{25}{15}\right)\)

\(=\frac47\cdot\frac{49}{15}\)

\(=\frac{49}{7}\cdot\frac{4}{15}=7\cdot\frac{4}{15}=\frac{28}{15}\)

c: Cách 1: \(\frac72:\left(\frac85-\frac23\right)\)

\(=\frac72:\left(\frac{24}{15}-\frac{10}{15}\right)\)

\(=\frac72:\frac{14}{15}=\frac72\cdot\frac{15}{14}=\frac{15}{2\cdot2}=\frac{15}{4}\)

a: \(=\left(\dfrac{5}{8}-\dfrac{28}{8}\right)\cdot\dfrac{5}{6}=\dfrac{-23}{8}\cdot\dfrac{5}{6}=\dfrac{-115}{48}\)

b: \(=\dfrac{4}{7}\cdot\dfrac{24+25}{15}=\dfrac{4}{7}\cdot\dfrac{49}{15}=\dfrac{28}{15}\)

c: \(=\dfrac{7}{2}:\dfrac{24-10}{15}=\dfrac{7}{2}\cdot\dfrac{15}{14}=\dfrac{15}{4}\)

bn oi tính bằng 2 cách ạ

a: \(\frac23+\left(\frac57+\frac{-2}{3}\right)\)

\(=\frac23+\frac57-\frac23\)

\(=\frac57\)

b: \(\left(-\frac14+\frac58\right)+\frac{-3}{8}\)

\(=\frac{-2}{8}+\frac58+\frac{-3}{8}\)

=0

c: \(\frac75\cdot\frac{8}{19}+\frac75\cdot\frac{12}{19}-\frac75\cdot\frac{1}{19}\)

\(=\frac75\left(\frac{8}{19}+\frac{12}{19}-\frac{1}{19}\right)\)

\(=\frac75\cdot\frac{19}{19}=\frac75\)

d: \(6\frac{3}{10}-\left(3\frac47+2\frac{3}{10}\right)\)

\(=6+\frac{3}{10}-3-\frac47-2-\frac{3}{10}\)

\(=1-\frac47=\frac77-\frac47=\frac37\)

e: \(\left(31,12-5,97\right)-\left(-68,88+4,03\right)\)

=31,12-5,97+68,88-4,03

=100-10

=90

f: \(3,7\cdot\left(-10,56\right)+3,7\cdot110,56\)

\(=3,7\cdot\left(-10,56+110,56\right)\)

\(=3,7\cdot100=370\)

\(\left(\dfrac{2}{7}+\dfrac{5}{7}\right)+\left(\dfrac{3}{5}+\dfrac{2}{5}\right)+\left(\dfrac{3}{8}+\dfrac{4}{8}+\dfrac{1}{8}\right)+\left(\dfrac{1}{9}+\dfrac{8}{9}\right)=1+1+1+1=4\)

A = (2 + 2²) + (2³ + 2⁴ ) +…(2¹⁹⁹ + 2²⁰⁰)

A = 6 + 2² (2 + 2² ) +… + 2¹⁹⁸ (2 + 2²)

A = 6 + 2² (6 ) +… + 2¹⁹⁸ (6)

A = 6(1 + 2² +… + 2¹⁹⁸)

Vậy A chia hết cho 6

a) \(\left(\frac{2}{7}+\frac{3}{8}+\frac{12}{7}+\frac{5}{8}\right).\frac{19}{36}\)

\(=\left\{\left(\frac{2}{7}+\frac{12}{7}\right)+\left(\frac{3}{8}+\frac{5}{8}\right)\right\}.\frac{19}{36}\)

\(=\left(\frac{14}{7}+\frac{8}{8}\right).\frac{19}{36}\)

\(=\left(2+1\right).\frac{19}{36}\)

\(3.\frac{19}{36}=\frac{19}{12}\)

5/8 + 7/12 + 3/8 = ( 5/8 + 3/8) + 7/12 = 1 + 7/12 = 19/12

( 2,7 + 4,3) + 3,59 = 7 + 3,59 = 10,59

= 29/24 + 3/8 = 19/12

= ( 2,7 + 4,3) + 3,59 = 7 + 3,59 = 10,59

A) 5/4 x X = 3/8 + 5/12

5/4 x X = 19/24

        X  = 19/24 : 5/4

        X  = 19/30

vậy x =...

B, 3 x 7/10 + 7/10 x 5 + 2 x 7/10

  = 7/10 x ( 3 + 5 + 2)

  = 7/10 x 10

  = 7

Giúp tớ với mọi người ơi

\(a.60\times\left(\frac{7}{12}+\frac{4}{15}\right)\)

\(=60\times\left(\frac{35}{60}+\frac{16}{60}\right)\)

\(=60\times\frac{51}{60}\)

\(=51\)

\(b.\frac{1}{2}\times\frac{2}{3}\times\frac{3}{4}\times\frac{4}{5}\times\frac{5}{6}\times\frac{6}{7}\times\frac{7}{8}\times\frac{8}{9}\)

\(=\frac{1\times2\times3\times4\times5\times6\times7\times8}{2\times3\times4\times5\times6\times7\times8\times9}\)

\(=\frac{1}{9}\)