\(3\sqrt{25}-\sqrt{36}-2\sqrt{16}=\sqrt{225}-\sqrt{36}-\sqrt{64}=15-6-8=1\)

`3\sqrt{25}-\sqrt{36}-2\sqrt{16}`

`=3\sqrt{5^2}-\sqrt{6^2}-2\sqrt{4^2}`

`=3.5-6-2.4=15-6-8=1`

=2/3+8/15x25/16

=2/3+5/6=9/6=3/2

`2/3 + 8/15 : 16/25`

`= 2/3 + 5/6`

`= 3/2`.

a) (16 . 25 + 480 : 6 ) : 240 - 1,5 . 1,2

 =>( 400 + 80 ) : 240 - 1,5 . 1,2

 => 480 : 240 - 1,5 . 1,2

 => 2 - 1,5 .1,2

  => 2- 1,8= 0,2

l-ike nhé

`25 - 15 : 5= 25 - 3 =22`

`101 × (16 – 7)= 101 xx 9=909`

`40 + 8 : 2= 40 + 4=44`

`48 : (8 : 2)= 48 : 4=12`

   \(\dfrac{2\times9\times16\times25}{12\times20\times30}\)

=  \(\dfrac{2\times3\times3\times4\times4\times5\times5}{3\times4\times4\times5\times5\times3\times2}\)

= \(\dfrac{2\times3\times3\times4\times4\times5\times5}{2\times3\times3\times4\times4\times5\times5}\)

= 1

=360000

ê nha

?

a) 450 – ( 25 – 10) = 450 – 15

                   = 435

450 – 25 – 10 = 425 – 10

                   = 415

b) 180 : 6 : 2 = 30 : 6

                   = 15

180 : ( 6 : 2 ) = 180 : 3

                   = 60

c) 410 – (50 +30) = 410 -80

                   = 330

410 - 50 + 30 = 360 + 30

                   = 390

d) 16 x (6 : 3) = 16 x 2

                   = 32

16 x 6 : 3 = 96 : 3

                   = 32

anh có công thức này cho m  

\(1^3+2^3+...+\left(n-1\right)^3+n^3=\left(1+2+...+n-1+n\right)^2=\left(\frac{n\left(n+1\right)}{2}\right)^2\) . m có thể chứng minh cái này bằng quy nạp

\(A=\sqrt{14^3+15^3+16^3+...+24^3+25^3}\)

\(=\sqrt{\left(1^3+2^3+....+13^3\right)+14^3+15^3+16^3+...+24^3+25^3-\left(1^3+2^3+....+13^3\right)}\)

\(=\sqrt{\left(25\cdot\frac{26}{2}\right)^2-\left(13\cdot\frac{14}{2}\right)^2}=312\)

a) 5

b) 11/6

\(\frac{5}{12}-\left|-12\right|-4\cdot\sqrt{\frac{25}{16}}+2015^0\)

\(=\frac{5}{12}-12-4\cdot\frac{5}{4}+1\)

\(=\frac{5}{12}-\frac{144}{12}-\frac{60}{12}+\frac{12}{12}\)

\(=\frac{5-144-60+12}{12}\)

\(=\frac{-187}{12}\)