dài quá mk lười lắm

em chưa học đâu!5a mà

Câu 1:

\(\frac{13}{19}\).(\(\frac{19}{26}\) - \(\frac{71}{43}\)) + \(\frac{71}{43}\).(\(\frac{13}{19}\) - \(\frac{86}{71}\))

= \(\frac{13}{19}\).\(\frac{19}{26}\) - \(\frac{13}{19}\).\(\frac{71}{43}\) + \(\frac{71}{43}\).\(\frac{13}{19}\) - \(\frac{71}{43}\).\(\frac{86}{71}\)

= \(\frac12\) - (\(\frac{13}{19}\).\(\frac{71}{43}\) - \(\frac{13}{19}\).\(\frac{71}{43}\)) - 2

= \(\frac12\) - 0 - 2

= 1/2 - 2

= 1/2 - 4/2

= - 3/2

=71+38/45- 43+8/45 +1+17/57

=(71 \(\frac{38}{45}-43\frac{8}{45}\))+ 1+17/57=28+2/3+1+17/57=29+55/57=29/55/57

49\(\frac{8}{23}\) - (5\(\frac{7}{32}\) + 14\(\frac{8}{23}\))

= 49\(\frac{8}{23}\) - 5\(\frac{7}{32}\) - 14\(\frac{8}{23}\)

= (49\(\frac{8}{23}\) - 14\(\frac{8}{23}\)) - 5\(\frac{7}{32}\)

= 35 - 5 - \(\frac{7}{32}\)

= 30 - \(\frac{7}{32}\)

= \(\frac{960}{32}\) - \(\frac{7}{32}\)

= 953/32

Câu b:

71\(\frac{38}{45}\) - (43\(\frac{8}{45}\) - 1\(\frac{17}{57}\))

= 71\(\frac{38}{45}\) - 43\(\frac{8}{45}\) - 1\(\frac{17}{57}\)

= 28\(\frac{30}{45}\) - 1\(\frac{17}{57}\)

= 28\(\frac23\) - 1\(\frac{17}{57}\)

= \(\frac{86}{3}\) - \(\frac{74}{57}\)

= \(\frac{1634}{57}\) - \(\frac{74}{57}\)

= \(\frac{1560}{57}\)

= \(\frac{520}{19}\)

\(71\frac{38}{45}-\left(43\frac{8}{45}-1\frac{17}{57}\right)\)

\(=71\frac{38}{45}-43\frac{8}{45}+1\frac{17}{57}\)

\(=\frac{86}{3}+\frac{74}{57}\)

\(=\frac{1708}{57}\)

Hc tốt #

sai me roi

\(=87+\frac{23}{59}+74+\frac{17}{71}+12+\frac{36}{59}+25+\frac{54}{71}\)

=\(\left(87+74+12+25\right)+\left(\frac{23}{59}+\frac{36}{59}\right)+\left(\frac{17}{71}+\frac{54}{71}\right)\)

=\(198+1+1=200\)

P/s: Bài này chỉ tính được giá trị "gần đúng" của biểu thức thôi nhé!

\(\frac{21}{54}+\frac{3}{75}:\frac{\left(\frac{39}{65}+0,415-\frac{33}{600}\right)\frac{21}{91}}{7^2-18,25+13\frac{15}{36}-16\frac{17}{102}}\)

\(\Leftrightarrow\frac{21}{54}+\frac{3}{75}:\frac{\left(0,6+0,415-0,055\right)0,23}{49-18,25+\frac{483}{36}-\frac{1649}{102}}\)

\(\Leftrightarrow\frac{21}{54}+\frac{3}{75}:\frac{\left(0,6+0,415-0,055\right)0,23}{49-18,25+13,41-16,1}\)

\(\Leftrightarrow\frac{21}{54}+\frac{3}{75}:\frac{0,96.0,23}{28,06}\Leftrightarrow\frac{21}{54}+\frac{3}{75}:\frac{0,2208}{28,06}\)

\(\Leftrightarrow\frac{21}{54}+\left(\frac{3}{75}:\frac{0,2208}{28,06}\right)\Leftrightarrow\frac{21}{54}+\left(\frac{3}{75}.\frac{28,06}{0,2208}\right)=\frac{21}{54}+\frac{61}{12}=\frac{197}{36}\)

P/s: Giải bài này mà mệt cả đầu =((

49\(\frac{8}{23}\) - (5\(\frac{7}{32}\) + 14\(\frac{8}{23}\))

= 49\(\frac{8}{23}\) - 5\(\frac{7}{32}\) - 14\(\frac{8}{23}\)

= (49\(\frac{8}{23}\) - 14\(\frac{8}{23}\)) - 5\(\frac{7}{32}\)

= 35 - 5 - \(\frac{7}{32}\)

= 30 - \(\frac{7}{32}\)

= \(\frac{960}{32}\) - \(\frac{7}{32}\)

= 953/32

Câu b:

71\(\frac{38}{45}\) - (43\(\frac{8}{45}\) - 1\(\frac{17}{57}\))

= 71\(\frac{38}{45}\) - 43\(\frac{8}{45}\) - 1\(\frac{17}{57}\)

= 28\(\frac{30}{45}\) - 1\(\frac{17}{57}\)

= 28\(\frac23\) - 1\(\frac{17}{57}\)

= \(\frac{86}{3}\) - \(\frac{74}{57}\)

= \(\frac{1634}{57}\) - \(\frac{74}{57}\)

= \(\frac{1560}{57}\)

= 520/19