Bài 1: tính
a) \(\dfrac{13}{32}+\dfrac{8}{24}+\dfrac{19}{32}+\dfrac{2}{3}\)
b)\(\dfrac{3}{4}.36\dfrac{1}{5}-\dfrac{3}{4}.2\dfrac{1}{5}\)
c) \(3^4:3.\dfrac{1}{27}\)
d) \(0,1.\sqrt{225}-\sqrt{\dfrac{1}{4}}\)
Bài 2: Tìm x
a) \(\dfrac{9}{5}.x=\dfrac{27}{10}\)
b)\(|x|+1,25=3\)
c) \(\left(2-x\right)^3=25\)
d) \(3^{x-1}+5.3^{x-1}=162\)
Bài 3: tìm x,y biết
\(|x+5|+\left(3y-4\right)^{2018}=0\)
Bài 4: so sánh
\(13\) và \(\sqrt{170}\)
a, \(\dfrac{13}{32}+\dfrac{8}{24}+\dfrac{19}{32}+\dfrac{2}{3}\)
\(=\left(\dfrac{13}{32}+\dfrac{19}{32}\right)+\left(\dfrac{1}{3}+\dfrac{2}{3}\right)\)
\(=\dfrac{32}{32}+\dfrac{3}{3}=1+1=2\)
b, \(\dfrac{3}{4}.36\dfrac{1}{5}-\dfrac{3}{4}.2\dfrac{1}{5}\)
\(=\dfrac{3}{4}.\left(36\dfrac{1}{5}-2\dfrac{1}{5}\right)\)
\(=\dfrac{3}{4}.\left[\left(36-2\right)+\left(\dfrac{1}{5}-\dfrac{1}{5}\right)\right]\)
\(=\dfrac{3}{4}.34=\dfrac{102}{4}=26\)
Bài 2:
a: x=27/10:9/5=27/10*5/9=135/90=3/2
b: =>|x|=1,75
=>x=1,75 hoặc x=-1,75
c: =>\(2-x=\sqrt[3]{25}\)
hay \(x=2-\sqrt[3]{25}\)
d: =>3^x-1*6=162
=>3^x-1=27
=>x-1=3
=>x=4
