Bài 1: Tính
a\()\) \(\frac{-25}{28}\) \(\times\) \(0,21\)
b\()\) \((\frac{13}{24}-\frac{29}{30})\) \(\div\) \(\left(-10,2\right)\)
Bài 2: Tìm x
a\()\) \(\left|x\right|\) \(=\) \(\frac{10}{3}\) b\()\) \(\left|x\right|\) \(=\) \(-5,1\)
c\()\) \(\left|x-\frac{11}{6}\right|\) \(=\) \(0\) d\()\) \(\left|x-\frac{5}{6}\right|\) \(=\) \(\frac{1}{2}\)
e\()\) \(\left|x+\frac{4}{9}\right|\) \(-\) \(\frac{1}{2}\) \(=\) \(\frac{3}{2}\)
Bài 3: Tìm giá trị nhỏ nhất \(\left|2x-1\right|+9\)
Bài 4: Tìm giá trị lớn nhất \(\frac{1}{8}-\left|x+3\right|\)
Bài 1:
\(a,A=\frac{-25}{28}.0,21=\frac{-25}{28}.\frac{21}{100}=\frac{-25.21}{28.100}=\frac{-1.25.3.7}{4.7.25.4}=\frac{-1.3}{4.4}=\frac{-3}{16}\)
\(b,B=\left(\frac{13}{24}-\frac{29}{30}\right):\left(-10,2\right)=\left(\frac{65}{120}-\frac{116}{120}\right):\frac{-51}{5}=\frac{-51}{120}.\frac{5}{-51}=\frac{-51.5}{120.\left(-51\right)}=\frac{-51.5}{5.24.\left(-51\right)}=\frac{1}{24}\)
