= 5,65 x (13,8 + 21,9) + 35,7 x (3,21 + 1,14) 

= 5,65 x 35,7 + 35,7 x 4,35

= 35,7 x (5,65 + 4,35) = 35,7 x 10 = 357

= 5,65 x (13,8 + 21,9) + 35,7 x (3,21 + 1,14)
= 5,65 x 35,7 + 35,7 x 4,35
= 35,7 x (5,65 + 4,35) = 35,7 x 10 = 357

k mk nha $_$

\(5,65\cdot13,8+35,7\cdot3,21+5,65\cdot21,9+35,7\cdot1,14\)

\(=5,65\cdot\left(13,8+21,9\right)+35,7\cdot\left(3,21+1,14\right)\)

\(=5,65\cdot35,7+35,7\cdot4,35\)

\(=35,7\cdot\left(5,65+4,35\right)\)

\(=35,7\cdot10=357\)

\(A=0,36.350+0,9.45.4+3.20.12\)
\(A=0,36.350+0,36.45+3,6.20\)
\(A=0,36.350+0,36.45+0,36.10.20\)
\(=0,36.\left(350+45+20.10\right)\)
\(A=0,36.595\)
\(A=214,2\)

\(b.12,8.3,2-y:4,6=35,06\)
\(40,96-y:4,6=35,06\)
\(y:4,6=40,96-35,06\)
\(y:4,6=5,9\)
\(y=5,9.4,6\)
\(y=27,14\)

\(y+y.\frac{3}{2}\)\(+y:\frac{2}{7}\)\(=21\)
\(y.1+y.\frac{3}{2}\)\(+y.\frac{7}{2}\)\(=21\)
\(y(1+\frac{3}{2}+\frac{7}{2}\)\()=21\)
\(y.6=21\)
\(y=\frac{21}{6}\)

Trả lời 

\(3,7.3,8+8,2.3,7-0,4.3,7.5\)

\(=3,7\left(3,8+8,2-2\right)=3,7.10=37\)

       \(3,7\times3,8+8,2\times3,7-0,4\times3,7\times5\)

\(=3,7\times\left[3,8+8,2-\left(0,4\times5\right)\right]\)

\(=3,7\times\left(3,8+8,2-2\right)\)

\(=3,7\times10\)

\(=37\)

\(x\times5,2+x\times4,8=25\\ \Rightarrow x\left(5,2+4,8\right)=25\\ \Rightarrow10x=25\\ \Rightarrow x=\dfrac{25}{10}=\dfrac{5}{2}\)

Vậy \(x=\dfrac{5}{2}\)

 \(X\times\left(5,2+4,8\right)=25\)

\(X\times10=25\)

=> \(X=\dfrac{25}{10}=2,5\)

dễ thì tự suy nghĩ sẽ tốt hơn

a,   17,58-6,35-5.65=17,58-(6,35+5.65)=17,58-12=5,58

b,    513,76-62,8+49,04

       =(513,76+49,04)-62,8

      =562,8-62,8=500

k cho mình nha bạn!

a; 17,58-6,35-5,65=17,58-(6,35+5,65)=17,58-12=5,58

b;513,76-62,8+49,04=513,76+49,04-62,8=562,8-62,8=500

a) 17,58 - 6,35 - 5,65 = 17,58 - ( 6,35 + 5,65 )

                                  = 17,58 -  12

                                  = 5,58

b) 513,76 - 62,8 + 49,04 = ( 513,76 + 49,04 ) - 62,8

                                        = 562,8 - 62,8

                                        = 500

\(3,7\times3,8+6,2\times3,7\\ =3,7\times\left(3,8+6,2\right)\\ =3,7\times10\\ =37\\ 56,8\times76,9-56,8\times76,8\\ =56,8\times\left(76,9-76,8\right)\\ =56,8\times0,1\\ =5,68\)

a)\(3,7\times3,8+6,2\times3,7\)
\(=3,7\times\left(3,8+6,2\right)\)
\(=3,7\times10=37\)
b)\(56,8\times76,9-56,8\times76,8\)
\(=56,8\times\left(76,9-76,8\right)\)
\(=56,8\times0,1=5,68\)

a,=3,7 x (3,8+6,2)=37

b,=56,8x(76,9-76,8)=5,68

Lời giải:
$3,8\times 2+1,9\times 8+7,6\times 2-17,7$

$=1,9\times 2\times 2+1,9\times 8+1,9\times 4\times 2-17,7$

$=1,9\times 4+1,9\times 8+1,9\times 8-17,7$

$=1,9\times (4+8+8)-17,7$

$=1,9\times 20-17,7=38-17,7=20,3$

A = 5,65 x 35,7 + 35,7 x 5,65

A = ( 5,65 x 35,7 ) x 2

A = 201,705 X 2

A = 403,41

số cần tìm là

[5.65x35.7]x2=403.41

đ/s:403.41

A = 5,65 x 35,7 + 35,7 x 5,65

A = (5,65 x 35,7) x 2

A = 201,705 x 2

A = 403,41