a: \(\frac{23}{45}\cdot\frac{15}{16}\cdot\frac{32}{23}+0,3\cdot x=5\frac35\cdot7\frac{7}{12}\cdot\frac{2}{27}\cdot\frac{5}{13}\)

=>\(\frac{12}{16}\cdot\frac{15}{45}+0,3x=\frac{28}{5}\cdot\frac{91}{12}\cdot\frac{2}{27}\cdot\frac{5}{13}\)

=>\(0,3x+\frac{1}{12}=\frac{91}{13}\cdot\frac{2}{12}\cdot\frac{28}{27}=7\cdot\frac16\cdot\frac{28}{27}=\frac{7\cdot14}{3\cdot27}=\frac{98}{81}\)

=>\(0,3x=\frac{98}{81}-\frac{1}{12}=\frac{365}{324}\)

=>\(x=\frac{365}{324}:0,3=\frac{365}{324\cdot0,3}=\frac{365}{97,2}=\frac{1825}{486}\)

b: \(\left\lbrack\left(35\frac57+2\frac34\right)-5\frac57+\frac14\right\rbrack:11+x=3\)

=>\(\left\lbrack35+\frac57+2+\frac34-5-\frac57+\frac14\right\rbrack:11+x=3\)

=>(32+1):11+x=3

=>33/11+x=3

=>x+3=3

=>x=0

a) ( 2011 - 125 x 8 : 4 ) x ( ( 48 : 8 x 6 )

= ( 2011 - 1000 : 4 ) x ( 6 x 6 )

= ( 2011 - 250 ) x 36

= 1761 x 36

= 63396

b) B = Không hiểu

c) C = 

\(\dfrac{7^{45}}{7}=7^{44}\)

\(49.7^{20}=7^2.7^{20}=7^{22}\)

\(\Rightarrow\dfrac{7^{45}}{7}=7^{44}>7^{22}=49.7^{20}\)

7⁴⁵ : 7 ²³ =  7²² 

49 \(\times\) 7²⁰ = 7² \(\times\) 7²⁰ = 7²²

7⁴⁵ : 7²³ = 49 \(\times\) 7²⁰

Ta có: \(\frac{19}{21}+\frac{15}{23}+\frac{15}{23}+\frac17-\frac{15}{23}\)

\(=\frac{19}{21}+\frac17+\frac{15}{23}\)

\(=\frac{19}{21}+\frac{3}{21}+\frac{15}{23}=\frac{22}{21}+\frac{15}{23}=\frac{22\times23+15\times21}{21\times23}=\frac{821}{483}\)

câu nầy hơn khó nên mình ko giải đc bạn đợ mình giải đã

1) 2763 + 152 = 2951

2)(-7) + (-14) = -21

\(\dfrac{-19}{23}\cdot\dfrac{13}{14}+\dfrac{13}{14}\cdot\dfrac{-15}{23}-\dfrac{13}{14}\cdot\dfrac{1}{23}\\ =\dfrac{13}{14}\cdot\left(\dfrac{-19}{23}+\dfrac{-15}{23}-\dfrac{1}{23}\right)\\ =\dfrac{13}{14}\cdot\dfrac{-35}{23}=\dfrac{-65}{46}\)

a) 19/35+15/19+16/35+23/19+4/15+11/15 = (19/35+16/35)+(15/19+23/19)+(4/15+11/15) = 1+2+1 = 4 b)4/17-7/15+13/17-8/15+5/8-7/16 = (4/17+13/17)-(7/15-8/15)+(5/8-7/16) = 1-1+3/16 =3/16

Câu a:

\(\frac{19}{35}\) + \(\frac{15}{19}\) + \(\frac{16}{35}\) + \(\frac{23}{19}\) + \(\frac{4}{15}\) + \(\frac{11}{15}\)

= (\(\frac{19}{35}\) + \(\frac{16}{35}\)) + (\(\frac{15}{19}\) + \(\frac{23}{19}\)) + (\(\frac{4}{15}+\frac{11}{15}\))

= \(\frac{35}{35}\) + \(\frac{38}{19}\) + \(\frac{15}{15}\)

= 1 + 2+ 1

= 3 + 1

= 4

Tính tổng hả
 

a] 352

b] 1470

c] 1400