\(=\frac{5^3\left(2^3+2+1\right)}{5.11}=\frac{5^3.11}{5.11}=5^2=25\)

\(a)4(15-18)-(3-5).(-3)^2\)

\(=4.\left(-3\right)-2.9\)

\(=6\)

\(b)(-4-11):(-3)\)

\(=-15:\left(-3\right)\)

\(=5\)

\(c)143-(-57)-(-2)^3.(-3)^0\)

\(=143+57+8.1\)

\(=208\)

\(d,\left(-5\right).\left[\left(90-2.5\right)-10^2+10:\left|-2\right|\right]\)

\(=-5.\left[80-100+10:2\right]\)

\(=-5.-15\)

\(=75\)

a) \(5^{3n+2}=25^{n+3}\)

\(\Leftrightarrow5^{3n+2}=5^{2\left(n+3\right)}\)

\(\Leftrightarrow3n+2=2\left(n+3\right)\)

\(\Leftrightarrow3n+2=2n+6\)

\(\Leftrightarrow n=4\)

b) \(6.5^{n-2}+10^2=2.5^3\left(n>1\right)\)

\(\Leftrightarrow6.5^{n-2}=2.5^3-10^2\)

\(\Leftrightarrow6.5^{n-2}=2.5^3-2^2.5^2\)

\(\Leftrightarrow6.5^{n-2}=2.5^2\left(5-2\right)\)

\(\Leftrightarrow6.5^{n-2}=2.5^2.3\)

\(\Leftrightarrow5^{n-2}=5^2\)

\(\Leftrightarrow n-2=2\)

\(\Leftrightarrow n=4\)

   (2 ^ 2 + 1) x (2 ^ 2 - 1) x (2 ^ 4 - 4 ^ 2)

= (2 ^ 2 + 1) x (2 ^ 2 - 1) x (  16  -   16  )

= (2 ^ 2 + 1) x (2 ^ 2 - 1) x 0

= 0

   ( 7 ^ 3 + 7 ^ 5) x (5 ^ 4 + 5 ^ 6) x ( 3 ^ 3 x 3 - 9 ^ 2)

= ( 7 ^ 3 + 7 ^ 5) x (5 ^ 4 + 5 ^ 6) x (    3 ^ 4   - 3 ^ 4)

= ( 7 ^ 3 + 7 ^ 5) x (5 ^ 4 + 5 ^ 6) x 0

= 0

   2 ^ 2 x 5 [( 5 ^ 2 + 2 ^ 3) : 11] - 2 ^ 4 + 2 x 10 ^ 3

=    4   x 5 [(   25  +    8  ) : 11] -    8   + 2 x  1000

=        20  (           33       :  11) -    8   +    2000

=        20 x                 3           -    8    +    2000

=                   60                     -     8    +   2000

=                                 2052

\(=0.04\cdot5-\dfrac{2^6\cdot3^{10}}{3^9\cdot2^6}=0.2-3=-2.8\)

Yc của đề là gì?

okiii

\(\dfrac{50}{13}+\dfrac{10}{13}-10\times\dfrac{5}{3}-2\times\dfrac{5}{13}\)

\(=\dfrac{50+10}{13}-\dfrac{50}{3}-\dfrac{10}{13}\) 

\(=\dfrac{60}{13}-\dfrac{10}{13}-\dfrac{50}{3}\)

\(=\dfrac{60-10}{13}-\dfrac{50}{3}\)

\(=\dfrac{50}{13}-\dfrac{50}{3}\)

\(=-\dfrac{500}{39}\)

Hừm bài này cj thấy khum tính thuận tiện đc ý:<<

\(x+\dfrac{4}{5}=2x\dfrac{5}{3}\)

<=> \(x+\dfrac{4}{5}=\dfrac{6x+5}{3}\)

<=> \(\dfrac{15x}{15}+\dfrac{12}{15}=\dfrac{5\left(6x+5\right)}{15}\)

<=> 15x + 12 = 5(6x + 5)

<=> 15x + 12 = 30x + 25

<=> 15x - 30x = 25 - 12

<=> -15x = 13

<=> x = \(\dfrac{-13}{15}\)