tính:
a).2/3+5/9-3/4
b).2/5x1/4:3/8
đầy đủ tick,lẹ
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a,\(\frac{7}{8}+\frac{3}{5}=\frac{35}{40}+\frac{24}{40}=\frac{35+24}{40}=\frac{59}{40}\)
b, \(\frac{20}{24}:\frac{5}{8}=\frac{20}{24}x\frac{8}{5}=\frac{20x8}{24x5}=\frac{160}{120}=\frac{4}{3}\)
c,\(\frac{8}{3}-\frac{2}{5}x\frac{1}{6}=\frac{8}{3}-\frac{2x1}{5x6}=\frac{8}{3}-\frac{1}{15}=\frac{13}{5}\)
a) 7/8 + 3/5 = 59/40
b) 20/24 : 5/8 = 4/3
c) 8/3 - 2/5 x 1/6 = 8/3 - 1/15 = 13/5
tính giá trị biểu thức :
a). ( 1 1/2 + 2 3/4) x 4 3/5
b).( 5 2/3 - 4 1/3 ) : 2 1/4
đầy đủ tick. lẹ elen
a) ( 1 1/2 + 2 3/4 ) x 4 3/5
= ( 3/2 + 11/4 ) x 23/5
= 17/4 x 23/5
= 391/20
b) ( 5 2/3 - 4 1/3 ) : 2 1/4
= ( 17/3 - 13/3 ) : 9/4
= 4/3 : 9/4
= 16/27
a: \(=\dfrac{-3-5-7}{4}=\dfrac{-15}{4}\)
b: \(=\dfrac{-6-5-2+6}{11}=\dfrac{-7}{11}\)
\(a;\frac{3}{7}+\frac{2}{3}=\frac{9}{21}+\frac{14}{21}=\frac{23}{21}\)
\(b;\frac{8}{7}-\frac{12}{28}\times\frac{7}{3}=\frac{8}{7}-\frac{3}{7}\times\frac{7}{3}=\frac{8}{7}-1=\frac{8}{7}-\frac{7}{7}=\frac{1}{7}\)
\(c;\frac{5}{6}\times3=\frac{15}{6}=\frac{5}{2}\)
\(d;\frac{3}{2}:\frac{7}{15}=\frac{3}{2}\times\frac{15}{7}=\frac{45}{14}\)
a) 3/7+2/3=9/21+14/21=23/21
b) 8/7-12/28*7/3=8/7-1=8/7-7/7-1/7
c) 5/6*3=5/2
d) 3/2:7/15=3/2*15/7=45/14
\(\left(x+\frac{1}{3}\right)\left(\frac{3}{4}-2x\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x+\frac{1}{3}=0\\\frac{3}{4}-2x=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{-1}{3}\\x=\frac{3}{8}\end{cases}}\)
Vậy \(x\in\left\{\frac{-1}{2};\frac{3}{8}\right\}\)
\(\frac{2}{3}+\frac{5}{9}-\frac{3}{4}=\frac{24}{36}+\frac{20}{36}-\frac{15}{36}\)\(=\frac{29}{36}\)
\(\frac{2}{5}\times\frac{1}{4}:\frac{3}{8}=\frac{2\times1\times8}{5\times4\times3}=\frac{16}{60}=\frac{4}{15}\)
a) 2/3 + 5/9 = 11/9 - 3/4 = 17/36
b) 2/5 * 1/4 = 1/10 : 3/8 = 4/15
Mik cũng ko chắc nữa có sai thì cho mink sorry bạn nha