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Bài 1 : Ta thấy
\(\dfrac{10}{15}=\dfrac{2}{3};\dfrac{14}{21}=\dfrac{2}{3}\Rightarrow10:15=14:21\Rightarrow\dfrac{10}{15}=\dfrac{14}{21}\)
\(\dfrac{16}{\left(-4\right)}=-4;\dfrac{12}{\left(-3\right)}=-4\Rightarrow16:\left(-4\right)=12:\left(-3\right)\Rightarrow\dfrac{16}{\left(-4\right)}=\dfrac{12}{\left(-3\right)}=-4\)
\(\dfrac{\left(-5\right)}{15}=\dfrac{\left(-1,2\right)}{3,6}=-\dfrac{1}{3}\Rightarrow\left(-5\right):15=\left(-1,2\right):3,6\)
\(\dfrac{2}{3}:\dfrac{1}{4}=\dfrac{2}{3}.4=\dfrac{8}{3};\dfrac{16}{9}:\dfrac{16}{24}=\dfrac{16}{9}.\dfrac{24}{16}=\dfrac{8}{3}\)
\(\Rightarrow\left(\dfrac{2}{3}:\dfrac{1}{4}\right)=\left(\dfrac{16}{9}:\dfrac{16}{24}\right)=\dfrac{8}{3}\)
Bài 2 :
a) \(14.15=10.21\Rightarrow\dfrac{14}{10}=\dfrac{21}{15}=\dfrac{7}{5}\)
b) \(0,2.4,5=0,6.1,5\Rightarrow\dfrac{0,2}{0,6}=\dfrac{1,5}{4,5}=\dfrac{1}{3}\)
a. 2,04 : (-3,12)
= 204/100 : (-312/100)
= 51/25 : (-78/25)
= 51/25 . (-25/78)
= -51/78
= -17/26
b. \(\left(-1\frac{1}{2}\right):1,25=\left(-\frac{3}{2}\right):\frac{125}{100}=\left(-\frac{3}{2}\right):\frac{5}{4}=\left(-\frac{3}{2}\right).\frac{4}{5}=-\frac{6}{5}\)
c. \(4:5\frac{3}{4}=4:\frac{23}{4}=4.\frac{4}{23}=\frac{16}{23}\)
d. \(10\frac{3}{7}:5\frac{3}{14}=\frac{73}{7}:\frac{73}{14}=\frac{73}{7}.\frac{14}{73}=\frac{14}{7}=\frac{2}{1}\)
MK SẼ CHO 3 K CHO BẠN NÀO NHANH+ĐÚNG NHẤT.
NHANH GIUP MK CAI COI
a) ta có: \(\frac{2,5}{5,5}=\frac{5}{11};4:12=\frac{4}{12}=\frac{1}{3}\)
\(\Rightarrow\frac{1}{3}=\frac{4}{12}\Rightarrow\frac{1}{4}=\frac{3}{12};\frac{4}{1}=\frac{12}{3};\frac{3}{1}=\frac{12}{4}\)
phần b bn dựa vào mak lm nha
\(\dfrac{9}{27}=\dfrac{\dfrac{3}{2}}{\dfrac{9}{2}}\\ \dfrac{9}{\dfrac{3}{2}}=\dfrac{27}{\dfrac{9}{2}}\\ \dfrac{27}{9}=\dfrac{\dfrac{9}{2}}{\dfrac{3}{2}}\\ \dfrac{\dfrac{9}{2}}{27}=\dfrac{\dfrac{3}{2}}{9}\)
\(\frac{28}{14}=2\)
\(\frac{5}{2}:2=\frac{5}{4}\)
\(\frac{8}{4}=2\)
\(\frac{1}{2}:\frac{2}{3}=\frac{3}{4}\)
\(\frac{3}{10}\)
\(\frac{21}{10}:7=\frac{3}{10}\)
\(3:\frac{3}{10}=\frac{1}{10}\)
từ đó ta có các tỉ lệ thức bằng nhau là:
28:14=8:4
3:10=2,1:7