\(2,5\) x \(9,5\) x \(4+20\) x \(9,5\) x \(0,5\) +\(9,5\) x \(8\) x \(1,25\)

\(=9,5\) x ( \(2,5\) x \(4+20\) x \(0,5\) + \(8\) x \(1,25\) )

\(=9,5\) x \(30\)

\(=285\)

=9.5*10+9.5*10+9.5+10

=9.5*(10+10+10)

=9.5*30

=2850

`2,5xx9,5xx4+20xx9,5xx0,5+9,5xx8xx1,25`

`=9,5xx10+9,5xx10+9,5xx10`

`=9,5xx(10+10+10)`

`=9,5xx30`

`=285`

= 9,5 x (2,5 + 4+20+0,5+8+1,25)

=9,5x36,25

=344,375

285

Đặt P= \(\dfrac{2.5^{22}-9.5^{21}}{25^{10}}\) : \(\dfrac{5.\left(3.7^{15}-19.7^{14}\right)}{\left(7^{16}+3.7^{15}\right)}\)

Có : \(\dfrac{2.5^{22}-9.5^{21}}{25^{10}}\)

= \(\dfrac{\left(2.5-9\right).5^{21}}{\left(5^2\right)^{10}}\)= \(\dfrac{\left(10-9\right).5^{21}}{5^{20}}\)=\(\dfrac{5^{21}}{5^{20}}\)= 5 (1)

Có: \(\dfrac{5.\left(3.7^{15}-19.7^{14}\right)}{\left(7^{16}+3.7^{15}\right)}\)

= \(\dfrac{5.\left[7^{14}.\left(3.7-19\right)\right]}{\left[7^{15}.\left(3+7\right)\right]}\)=\(\dfrac{5.7^{14}.2}{7^{15}.10}\)=\(\dfrac{10.7^{14}}{7^{15}.10}\)=\(\dfrac{1}{7}\) (2)

Từ (1) và (2) suy ra:

A= 5:\(\dfrac{1}{7}\)=5.7=35

Vậy A=35 hay \(\dfrac{2.5^{22}-9.5^{21}}{25^{10}}\):\(\dfrac{5.\left(3.7^{15}-19.7^{14}\right)}{\left(7^{16}+3.7^{15}\right)}\)= 35

\(P=\dfrac{2.5^{22}-9.5^{20}}{25^{10}}:\dfrac{5\left(3.7^{15}-19.7^{14}\right)}{7^{16}+3.7^{15}}\)

\(=\dfrac{5^{20}\left(2.5^2-9\right)}{5^{20}}:\dfrac{5.7^{14}\left(3.7-19\right)}{7^{15}\left(7+3\right)}\)

\(=\left(2.5^2-9\right):\dfrac{5\left(3.7-19\right)}{7.10}\)

\(=\dfrac{7.10\left(2.5^2-9\right)}{5\left(3.7-19\right)}\)

\(=\dfrac{7.2\left(2.5^2-9\right)}{3.7-19}\)

\(=\dfrac{14.41}{21-19}\)

\(=\dfrac{14}{2}\cdot41=7.41=287\)

C nha bạn

k mình đi

chúc bạn học tốt

\(-\dfrac{5}{9}\times\dfrac{5}{11}+\dfrac{6}{9}\times\dfrac{5}{11}+\dfrac{5}{9}\)

\(=\dfrac{5}{11}\times\left(-\dfrac{5}{9}+\dfrac{6}{9}+\dfrac{5}{9}\right)\)

\(=\dfrac{5}{11}\times\dfrac{6}{9}\)

\(=\dfrac{30}{99}\)

\(=\dfrac{10}{33}\)

Cho mình sửa lại ạ:

\(-\dfrac{5}{9}\times\dfrac{5}{11}+\dfrac{6}{9}\times\dfrac{5}{11}+\dfrac{5}{9}\)

\(=\dfrac{5}{11}\times\left(-\dfrac{5}{9}+\dfrac{6}{9}\right)+\dfrac{5}{9}\)

\(=\dfrac{5}{11}\times\dfrac{1}{9}+\dfrac{5}{9}\)

\(=\dfrac{5}{99}+\dfrac{5}{9}\)

\(=\dfrac{60}{99}\)

\(=\dfrac{20}{33}\)

6,8

9,5 - x = 2,7

x = 9,5 - 2,7

x = 6,8

31