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Câu 1: Tìm x:
a) 2/5× x =(thiếu đề)
8/7: x =4/5
x=8/7:4/5
x=10/7
Câu 2: Tính bằng cách thuận tiện nhất
5/9× 8/17 + 4/9 × 8/17
=(5/9+4/9)x8/17
=1x8/17=8/17
\(a.14,52\div1,5-9,81\div1,5\)
\(=\left(14,52-9,81\right)\div1,5\)
\(=4,71\div1,5=3,14\)
\(b.\frac{5}{9}:\frac{4}{7}+\frac{13}{9}\times\frac{7}{4}\)
\(=\frac{5}{9}\times\frac{7}{4}+\frac{13}{9}\times\frac{7}{4}\)
\(=\left(\frac{5}{9}+\frac{13}{9}\right)\times\frac{7}{4}\)
\(=\frac{18}{9}\times\frac{7}{4}\)
\(=2\times\frac{7}{4}\)
\(=\frac{7}{2}\)
14,52:1,5-9,81:1,5=( 14,52-9,81 ) : 1,5
=4,71:1,5
=3,14
con thứ 2 thì mình chịu, bạn tự làm nha.
học tốt lên nhé. mình chỉ biết làm luôn thôi nhé.
a: =9/13+4/13+2/9+7/9
=1+1
=2
b: =(44-17-23)/55
=4/55
c: =100+19,25
=119,25
d: =98,3-38
=60,3
a) 47,54+18,72+5,13-17,54-7,72+4,87=(47,54-17,54)+(18,72-7,72)+(4,87+5,13)=30+11+10=51
b)4/7+7/13+17/9+19/13-8/9+17/7=(4/7+17/7)+(7/13+19/13)+(17/9-8/9)=3+2+1=6
\(a.=\frac{4}{13}\times\frac{13}{4}\times\frac{2}{3}\times\frac{3}{2}\)
\(=1\times1\)
\(=1\)
\(b.=\frac{19}{13}+\frac{7}{13}+\frac{14}{6}+\frac{4}{6}+\frac{1}{9}+\frac{17}{9}\)
\(=\frac{26}{13}+\frac{18}{6}+\frac{18}{9}\)
\(=2+3+2\)
\(=7\)
4/13 * 2/3 * 13/4* 3/2= (4/13 * 13/4 )* (2/3 * 3*2) = 1*1=1
19/13 + 14/6 + 1/9 + 4/6 + 7/13 + 17/9 = (19/13 + 7/13) + (14/6 + 4/6) + (1/9 + 17/9) = 2 + 3 + 2 =7
\(\frac{4}{6}+\frac{7}{13}+\frac{17}{9}+\frac{19}{13}+\frac{1}{9}+\frac{14}{6}\)
\(=\left(\frac{4}{6}+\frac{14}{6}\right)+\left(\frac{7}{13}+\frac{19}{13}\right)+\left(\frac{17}{9}+\frac{1}{9}\right)\)
\(=3+2+2=7\)
4/6 + 7/13 + 17/9 + 19/13 + 1/9 + 14/6. = ( 4/6 + 14/6 ) + ( 7/13 + 19/13 ) + ( 17/9 + 1/9 ). = 18/6 + 26/13 + 18/9. = 3 + 2 + 2 = 7.
\(\dfrac{2}{3}+\dfrac{7}{13}-\dfrac{17}{9}+\dfrac{19}{13}-\dfrac{1}{9}+\dfrac{7}{3}\)
\(=\left(\dfrac{2}{3}+\dfrac{7}{3}\right)+\left(\dfrac{7}{13}+\dfrac{19}{13}\right)-\left(\dfrac{17}{9}+\dfrac{1}{9}\right)\)
\(=\dfrac{9}{3}+\dfrac{26}{13}-\dfrac{18}{9}\)
\(=3+2-2\)
\(=3\)
\(\frac{5}{9}:\frac{4}{7}+\frac{13}{9}.\frac{7}{4}\)
= \(\frac{5}{9}.\frac{7}{4}+\frac{13}{9}.\frac{7}{4}\)
= \(\left(\frac{5}{9}+\frac{13}{9}\right).\frac{7}{4}\)
=\(\frac{18}{9}.\frac{7}{4}\)
=2.7/4 = 7/2
\(\frac{5}{9}:\frac{4}{7}+\frac{13}{9}.\frac{7}{4}\)
\(=\frac{5}{9}.\frac{7}{4}+\frac{13}{9}.\frac{7}{4}\)
\(=\frac{7}{4}.\left(\frac{5}{9}+\frac{13}{9}\right)\)
\(=\frac{7}{4}.2\)
\(=\frac{7}{2}\)
Chúc bạn học tốt ~