\(A=\sqrt{12}+2\sqrt{27}+3\sqrt{45}-9\sqrt{48}\)

\(=2\sqrt{3}+6\sqrt{3}+9\sqrt{5}-36\sqrt{3}\)

\(=9\sqrt{5}-28\sqrt{3}\)

\(B=\left(\sqrt{48}-2\sqrt{75}+\sqrt{108}-\sqrt{147}\right):\sqrt{3}\)

\(=4-2\cdot5+6-7\)

\(=4-10+6-7\)

=-7

A=\(\sqrt{12}\)+2\(\sqrt{27}\)+3\(\sqrt{45}\) -9\(\sqrt{48}\)

  =\(\sqrt{4.3}\) +2\(\sqrt{9.3}\)+3\(\sqrt{9.5}\) -9\(\sqrt{16.3}\)

  =2\(\sqrt{3}\) +6\(\sqrt{3}\)+9\(\sqrt{5}\) -36\(\sqrt{3}\)

   =\(\sqrt{3}\)(2+6-36) + 9\(\sqrt{5}\)

   =9\(\sqrt{5}\)- 28\(\sqrt{3}\)

Những phân số bằng 4/9 là : 48/108 , 80/180 

Phân số 4/9 bằng các phân số là : 48/108 , 80/180 

Ta thấy :

\(\frac{48}{108}=\frac{4}{9}\)

\(\frac{80}{180}=\frac{4}{9}\)

\(\frac{60}{130}=\frac{6}{13}\)

\(\frac{135}{270}=\frac{1}{2}\)

Vậy 4/9 = 48/108; 80/180.

\(\dfrac{48}{108}=\dfrac{48:12}{108:12}=\dfrac{4}{9}\\ \dfrac{80}{180}=\dfrac{80:20}{180:20}=\dfrac{4}{9}\\ \dfrac{60}{130}=\dfrac{60:10}{130:10}=\dfrac{6}{13}\\ \dfrac{135}{270}=\dfrac{135:135}{270:135}=\dfrac{1}{2}\)

=> Chọn 2 phân số: 48/108 và 80/180

7*9+14*27+21*63/21*27+42*48+63*108

=63+7*2*9*3+21*63/7*3*9*3+21*2*16*3+63*108

=63+63*6+21*63/63*9+63*32+63*108

=63*(1+6+21)/63*(9+32+108)

=1+6+21/9+32+108

=28/149

bằng 77760 nha

451 x 96 + 48 x 108 - 48 x 610 

= 451 x 48 x 2 + 48 x 108 - 48 x 610

= 48 x 2 x 451 + 48 x 108 - 48 x 610

= 48 x 902 + 48 x 108 - 48 x 610

= 48 x ( 902 + 108 - 610 )

= 48 x 400

= 19200

TL

các P/s bằng nhau là

   3/4=36/48; 9/13=54/78=108/256; 5/7=75/105; 2/9=42/189.

nha  bn

HT

TL:

\(\frac{3}{4}=\frac{36}{48}\)

\(\frac{2}{9}=\frac{42}{189}\)

\(\frac{5}{7}=\frac{75}{105}\)

\(\frac{9}{13}=\frac{108}{156}\)

Còn dư phân số : 54/78

_HT_

a, X x (1/3 + 1/6)=48

     3/6 x X = 48

     X = 96

b,x : 2/5 = 5/9 

    x= 25/18 

c, (002 là sao bạn)

d,X - 23,7 = 72,3

     X=  96

e, (108-48) : X =30

      60 : X = 30

       X = 2

f, (59,35 + 40,65) : X = 50

    100 : X = 50 

     X = 2

\(=3\sqrt{3}+4\sqrt{3}-6\sqrt{3}-2\sqrt{3}=-\sqrt{3}\)

\(=3\sqrt{3}+4\sqrt{3}-6\sqrt{3}-2\sqrt{3}=-\sqrt{3}\)