=6227.978567

a, \(x\) - \(\dfrac{2}{7}\) = \(\dfrac{4}{5}\) \(\times\) \(\dfrac{15}{24}\)

    \(x\) - \(\dfrac{2}{7}\) = \(\dfrac{1}{2}\)

    \(x\)        = \(\dfrac{1}{2}\) + \(\dfrac{2}{7}\)

    \(x\)       = \(\dfrac{11}{14}\)

b, \(x\): \(\dfrac{2}{7}\) = \(\dfrac{9}{8}\) - \(\dfrac{15}{6}\)

     \(x\):  \(\dfrac{2}{7}\) = - \(\dfrac{11}{8}\)

     \(x\)      = - \(\dfrac{11}{8}\) \(\times\) \(\dfrac{2}{7}\)

     \(x\)     = - \(\dfrac{11}{28}\)

a) x = 11/14

b) x = -11/28

\(a,\) \(x\) \(-\) \(\dfrac{2}{7}\) \(=\dfrac{4}{5}\times\dfrac{15}{24}\)

   \(x-\dfrac{2}{7}=\dfrac{1}{2}\)

  \(x\)          \(=\) \(\dfrac{1}{2}+\dfrac{2}{7}\)

 \(x\)           \(=\) \(\dfrac{11}{14}\)

\(b,\) \(x\div\dfrac{2}{7}=\dfrac{9}{8}-\dfrac{15}{6}\)                                               

\(x\div\dfrac{2}{7}=\dfrac{87}{24}\)

\(x=\dfrac{87}{24}\times\dfrac{2}{7}\)

\(x=\dfrac{87}{84}\)

\(\frac{2^4.2^6}{\left(2^5\right)^2}-\frac{2^5.15^3}{6^3.10^2}=\frac{2^{10}}{2^{10}}-\frac{2^5.\left(3.5\right)^3}{\left(2.3\right)^3.\left(2.5\right)^2}=1-\frac{2^5.3^3.5^3}{2^3.3^3.2^2.5^2}\)

\(=1-\frac{2^5.3^3.5^3}{\left(2^3.2^2\right).3^3.5^2}=1-\frac{2^5.3^3.5^3}{2^5.3^3.5^2}=\frac{1.1.5}{1.1.1}=5\)

làm lại cái đoạn cuối

\(=1-\frac{1.1.5}{1.1.1}=1-5=-4\)

y-2/7=4/5x15/24

y-2/7=4/5x5/8

y-2/7=1/2

y=1/2+2/7

y=7/14+4/14

y=11/14

x ở trên là dấu nhân

tính giá trị biểu thức

\(\dfrac{8^5\cdot15^4}{2^{15}\cdot3^4\cdot5^3}=\dfrac{2^{15}\cdot3^4\cdot5^4}{2^{15}\cdot3^4\cdot5^3}=5\)

\(\dfrac{8^5.15^4}{2^{15}.3^4.5^3}=\dfrac{\left(2^3\right)^5.3^4.5^4}{2^{15}.3^4.5^3}=\dfrac{2^{15}.3^4.5^4}{2^{15}.3^4.5^3}=5\)

a) x= 10; y = 25

b) x + 2 y + 10 = 1 5  => ( x = 2).5 = ( y = 10).1=> 5.x + 10 = y + 10

=> 5.x = y mà y – 3.x = 2

Nên  x = 1; y = 5

c) x = 20 ; y = 25