Bài 4:
\(\dfrac{3}{4}+y:\dfrac{2}{5}=\dfrac{37}{16}\)
\(\Rightarrow y:\dfrac{2}{5}=\dfrac{37}{16}-\dfrac{3}{4}\)
\(\Rightarrow y:\dfrac{2}{5}=\dfrac{25}{16}\)
\(\Rightarrow y=\dfrac{2}{5}\cdot\dfrac{25}{16}\)
\(\Rightarrow y=\dfrac{5}{8}\)
________________
\(456+y:87=23987\)
\(\Rightarrow y:87=23987-456\)
\(\Rightarrow y:87=23531\)
\(\Rightarrow y=23531\cdot87\)
\(\Rightarrow y=2047197\)
a)\(\dfrac{4}{5}\times\dfrac{5}{8}:\dfrac{4}{5}\)
\(=\left(\dfrac{4}{5}:\dfrac{4}{5}\right)\times\dfrac{5}{8}\)
\(=1\times\dfrac{5}{8}=\dfrac{5}{8}\)
b)\(\dfrac{5}{6}+\left(\dfrac{1}{2}:\dfrac{3}{2}+\dfrac{4}{5}\right)\)
\(=\dfrac{5}{6}+\left(\dfrac{1}{3}+\dfrac{4}{5}\right)\)
\(=\dfrac{5}{6}+\dfrac{17}{15}\)
\(=\dfrac{59}{30}\)
Bài 2:
a) \(\dfrac{3}{4}+y:\dfrac{2}{5}=\dfrac{37}{16}\)
\(y:\dfrac{2}{5}=\dfrac{37}{16}-\dfrac{3}{4}\)
\(y:\dfrac{2}{5}=\dfrac{25}{16}\)
\(y=\dfrac{25}{16}\times\dfrac{2}{5}\)
\(y=\dfrac{5}{8}\)
b)\(456+y:87=23987\)
\(y:87=23987-456\)
\(y:87=23531\)
\(y=23531\times87\)
\(y=2047197\)
a) 4/5 x 5/8 : 4/5
= 5/8
b) 5/6 + ( 1/2 : 3/2 + 4/5)
= 5/6 + (1/3 + 4/5)
= 5/6 + 17/15
= 59/30
B4:
3/4 + y : 2/5 = 37/16
y : 2/5 = 25/16
y = 5/8.
456 + y : 87 = 23987
y : 87 = 23531
y = 2047197.
Bài 3 :
a) \(\dfrac{4}{5}x\dfrac{5}{8}:\dfrac{4}{5}=\dfrac{1}{2}.\dfrac{5}{4}=\dfrac{5}{8}\)
b) \(\dfrac{5}{6}+\left(\dfrac{1}{2}:\dfrac{3}{2}+\dfrac{4}{5}\right)=\dfrac{5}{6}+\left(\dfrac{1}{2}.\dfrac{2}{3}+\dfrac{4}{5}\right)=\dfrac{5}{6}+\left(\dfrac{1}{3}+\dfrac{4}{5}\right)\)
\(=\dfrac{5}{6}+\left(\dfrac{5}{15}+\dfrac{12}{15}\right)=\dfrac{5}{6}+\dfrac{17}{15}=\dfrac{25}{30}+\dfrac{17}{30}=\dfrac{42}{30}=\dfrac{7}{5}\)
Bài 4:
\(\dfrac{3}{4}+y:\dfrac{2}{5}=\dfrac{37}{16}\Rightarrow y:\dfrac{2}{5}=\dfrac{37}{16}-\dfrac{3}{4}\Rightarrow y:\dfrac{2}{5}=\dfrac{37}{16}-\dfrac{12}{16}\)
\(\Rightarrow y:\dfrac{2}{5}=\dfrac{25}{16}\Rightarrow y=\dfrac{25}{16}x\dfrac{2}{5}=\dfrac{25}{8}\)
\(456+y:87=23987\Rightarrow y:87=23987-456\Rightarrow y:87=23531\)
\(\Rightarrow y=23531.87=\text{2047197}\)
