1,Tìm x
a, x + 11/30 = 19/20
b, x : 3 1/5 = 1 1/2
c, 7 x X - 3 x X = 3,2
d, X x 13 - x : 1/4 = 36
e, 8,75 x X + 1,25 x X = 20
2.Tính
a, 3/5 + 25 - 1/5
b, 6/7 : 1/2 x 3/4 - 5/8
c, ( 1 - 1/2) x (1 - 1/3) x (1 - 1/4) x (1 - 1/5)
d, 5932 + 6001 x 5931/5932 x 6001 - 69
Giúp mình với nhé !!
1.
a,x+11/30=19/20
=> x=19/20-11/30
=> x=7/12
b,\(x:3\dfrac{1}{5}=1\dfrac{1}{2}\)
\(\Rightarrow x:\dfrac{16}{5}=\dfrac{3}{2}\)
\(\Rightarrow x=\dfrac{3}{2}\cdot\dfrac{16}{5}\)
\(\Rightarrow x=\dfrac{24}{5}\)
c, \(7\cdot x-3\cdot x=3,2\)
\(\Rightarrow x\left(7-3\right)=3,2\)
\(\Rightarrow4x=3,2\)
\(\Rightarrow x=3,2:4\)
\(\Rightarrow x=0,8\)
d, \(x\cdot13-x:\dfrac{1}{4}=36\)
\(\Rightarrow x\cdot13-x\cdot4=36\)
\(\Rightarrow x\left(13-4\right)=36\)
\(\Rightarrow12x=36\)
\(\Rightarrow x=36:12\)
\(\Rightarrow x=3\)
e,\(8,75\cdot x+1,25\cdot x=20\)
\(\Rightarrow x\left(8,75+1,25\right)=20\)
\(\Rightarrow10x=20\)
\(\Rightarrow x=20:10\)
\(\Rightarrow x=2\)
2.
a. \(\dfrac{3}{5}+25-\dfrac{1}{5}\)
\(=\left(\dfrac{3}{5}-\dfrac{1}{5}\right)+25\)
\(=\dfrac{2}{5}+25\)
\(=\dfrac{127}{5}=25,4\)
b. \(\dfrac{6}{7}:\dfrac{1}{2}\cdot\dfrac{3}{4}-\dfrac{5}{8}\)
\(=\dfrac{6}{7}\cdot2\cdot\dfrac{3}{4}-\dfrac{5}{8}\)
\(=\dfrac{12}{7}\cdot\dfrac{3}{4}-\dfrac{5}{8}\)
\(=\dfrac{9}{7}-\dfrac{5}{8}\)
\(=\dfrac{37}{56}\)
c,\(\left(1-\dfrac{1}{2}\right)\cdot\left(1-\dfrac{1}{3}\right)\cdot\left(1-\dfrac{1}{4}\right)\cdot\left(1-\dfrac{1}{5}\right)\)
\(=\dfrac{1}{2}\cdot\dfrac{2}{3}\cdot\dfrac{3}{4}\cdot\dfrac{4}{5}\)
\(=\dfrac{1\cdot2\cdot3\cdot4}{2\cdot3\cdot4\cdot5}\)
\(=\dfrac{1}{5}\)
d. \(\dfrac{5932+6001\cdot5931}{5932\cdot6001-69}\)
\(=1\)