812 x 5 + 812 x 7 - 7 - 812 x 2 ???

 toàn câu hỏi sai

a: \(1\frac37-\frac78+2\frac45:2\)

\(=\frac{10}{7}-\frac78+\left(2+\frac45\right):2\)

\(=\frac{80}{56}-\frac{49}{56}+1+\frac25=\frac{31}{56}+\frac75=\frac{155+392}{280}=\frac{547}{280}\)

b: \(812\times X+188\times X=10000\)

=>\(X\times\left(812+188\right)=10000\)

=>\(1000\times X=10000\)

=>X=10000:1000=10

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

=7/10(3+5+2)

=7/10*10

=7

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

= 7/10 x (3 + 5 + 2)

= 7/10 x 10

= 7

\(\dfrac{7}{10}\times\left(3+5+2\right)=\dfrac{7}{10}\times10=\dfrac{70}{10}=7\)

`3xx7/10+7/10xx5+2xx7/10`

`=7/10xx(3+5+2)`

`=7/10xx10`

`=7`

=3/5*\((\)2/7+4/7\()\)+2/5

=3/5*6/7+2/5

=18/35+2/5

=32/35

`2/5 xx 4/7 + 3/5 xx 4/7`

`= 4/7 xx (2/5 + 3/5)`

`= 4/7 xx 1`

`= 4/7`

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

`[` Tham Khảo `]`

`35 xx 5 - 35 xx 2 + 35 xx7`

`= 35 xx (5-2+7)`

`= 35 xx 10`

`=350`

= 35 × (5 + 7 - 2)

= 35 × 10

= 350

lx

Uả cái j zị