tính giá trị biểu thức:a) \(\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\frac{15}{7}+\frac{15}{9}-\frac{15}{11}}\) b) \(\frac{4+\frac{4}{73}-\frac{4}{115}}{5+\frac{5}{73}-\frac{1}{23}}\)
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Mk chỉ biết câu a thôi
a) \(\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\frac{15}{7}+\frac{15}{9}-\frac{15}{11}}\)
= \(\frac{5\cdot\left(\frac{1}{7}+\frac{1}{9}-\frac{1}{11}\right)}{15\cdot\left(\frac{1}{7}+\frac{1}{9}-\frac{1}{11}\right)}\)
= \(\frac{5}{15}\)
= \(\frac{1}{3}\)
Chúc bạn học tốt
\(B=\frac{1}{3}-\frac{3}{4}+0,6+\frac{1}{64}-\frac{2}{9}-\frac{1}{36}+\frac{1}{15}\)
\(\Rightarrow B=\frac{3}{15}-\frac{48}{64}+\frac{9}{15}+\frac{1}{64}-\frac{8}{36}-\frac{1}{36}+\frac{1}{15}\)
\(\Rightarrow B=\frac{3}{15}+\frac{9}{15}+\frac{1}{15}+\left(-\frac{48}{64}+\frac{1}{64}\right)+\left(-\frac{8}{36}-\frac{1}{36}\right)\)
\(\Rightarrow B=\frac{13}{15}-\frac{47}{64}-\frac{1}{4}\)
\(\Rightarrow B=-\frac{113}{960}\)
\(C=0\)
\(D=\frac{1}{99}-\frac{1}{99.98}-...-\frac{1}{3.2}-\frac{1}{2.1}\)
\(\Rightarrow D=\frac{1}{99}-\frac{1}{99}+\frac{1}{98}-\frac{1}{98}+...-\frac{1}{3}+\frac{1}{2}-\frac{1}{2}+1\)
\(\Rightarrow D=1\)
D= \(\frac{1}{99}-\frac{1}{99.98}-\frac{1}{98.97}......-\frac{1}{3.2}-\frac{1}{2.1}\)
=\(\frac{1}{99}-\left(\frac{1}{1.2}+\frac{1}{2.3}+.......+\frac{1}{97.98}+\frac{1}{98.99}\right)\)
=\(\frac{1}{99}-\left(1-\frac{1}{2}+\frac{1}{2}-.....-\frac{1}{98}-\frac{1}{99}\right)\)
=\(\frac{1}{99}-\left[1-(\frac{1}{2}-\frac{1}{2}+......+\frac{1}{98}-\frac{1}{99})\right]\)
=\(\frac{1}{99}-\left(1-0-0-.....-0-\frac{1}{99}\right)\)
=\(\frac{1}{99}-1-\frac{1}{99}\)
=1
Phần 1)Đầu tiên bạn nhân B với 1 phần 4 rồi tính đến đoạn gần cuối sẽ ra 1/3 - 1/35 rồi quy đòng rồi tính sẽ ra kêt quả cuối là 32/105 nha
Mình lười lắm nên chỉ help 1 phần thui nha sr
= 1/3 - 1/3 + 5/7 - 5/7 - 7/9 + 7/9 +9/11 - 9/11 -11/13 + 11/13 +13/15
= 0 + 0 - 0 + 0 -0 + 13/15
= 0 + 13/15
= 13/15
\(\frac{1}{3}-\frac{3}{5}+\frac{5}{7}-\frac{7}{9}+\frac{9}{11}-\frac{11}{13}+\frac{13}{15}+\frac{11}{13}-\frac{9}{11}+\frac{7}{9}-\frac{5}{7}+\frac{3}{5}-\frac{1}{3}\)
\(=\left(\frac{1}{3}-\frac{1}{3}\right)+\left(\frac{3}{5}-\frac{3}{5}\right)+\left(\frac{5}{7}-\frac{5}{7}\right)+\left(\frac{7}{9}-\frac{7}{9}\right)+\left(\frac{9}{11}-\frac{9}{11}\right)+\left(\frac{11}{13}-\frac{11}{13}\right)+\frac{13}{15}\)
\(=0+0+0+0+0+0+\frac{13}{15}\)
\(=\frac{13}{15}\)
\(\frac{11}{9}.\frac{15}{4}-\frac{11}{4}.\frac{7}{9}-\frac{11}{9}.\frac{5}{4}\)
=\(\frac{11}{9}.\frac{15}{4}-\frac{11}{9}.\frac{7}{4}-\frac{11}{9}.\frac{5}{4}\)
=\(\frac{11}{9}\).\(\left(\frac{15}{4}-\frac{7}{4}-\frac{5}{4}\right)\)
=\(\frac{11}{9}\).\(\frac{3}{4}\)
=\(\frac{11.3}{3.3.4}\)
=\(\frac{11}{12}\)
Chúc bn học tốt
Simplify 0.24*(-15)/4
Simplify 5/9/(1/11-5/22)+5/9/(1/15-2/3)
\(a.\frac{108}{119}.\frac{107}{211}+\frac{108}{119}.\frac{104}{211}=\frac{108}{119}.\left(\frac{107}{211}+\frac{104}{211}\right)=\frac{108}{119}.1=108\)
a) \(\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\frac{15}{7}+\frac{15}{9}-\frac{15}{11}}=\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\frac{\left(10+5\right)}{7}+\frac{\left(10+5\right)}{9}-\frac{\left(10+5\right)}{11}}\)
\(=\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\left(\frac{10}{7}+\frac{5}{7}\right)+\left(\frac{10}{9}+\frac{5}{9}\right)-\left(\frac{10}{11}+\frac{5}{11}\right)}=\frac{0}{\frac{10}{7}+\frac{10}{9}-\frac{10}{11}}=0\)
b) \(\frac{4+\frac{4}{73}-\frac{4}{115}}{5+\frac{5}{73}-\frac{1}{23}}=\frac{4+\frac{4}{73}-\frac{4}{115}}{5+\frac{1}{73}+\frac{4}{73}-\frac{5}{115}}=\frac{4+\frac{4}{73}-\frac{4}{115}}{5+\frac{1}{73}+\frac{4}{73}-\frac{4}{115}+\frac{1}{115}}\)
\(=\frac{4}{5+\frac{1}{73}-\frac{1}{115}}=0\)
tth làm dài quá, làm gọn hơn nè
a, \(\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\frac{15}{7}+\frac{15}{9}-\frac{15}{11}}=\frac{5\left(\frac{1}{7}+\frac{1}{9}-\frac{1}{11}\right)}{15\left(\frac{1}{7}+\frac{1}{9}-\frac{1}{11}\right)}=\frac{5}{15}=\frac{1}{3}\)
b, \(\frac{4+\frac{4}{73}-\frac{4}{115}}{5+\frac{5}{73}-\frac{1}{23}}=\frac{4+\frac{4}{73}-\frac{4}{115}}{5+\frac{5}{73}-\frac{5}{115}}=\frac{4\left(1+\frac{1}{73}-\frac{1}{115}\right)}{5\left(1+\frac{1}{73}-\frac{1}{115}\right)}=\frac{4}{5}\)