1)Thực hiện phép tính nhanh:
a)\(\left(1-\frac{1}{2}\right)^2-2013^0+\sqrt{16+9}\)
b)\(-3\frac{1}{2}.104+3\frac{1}{2}.\left(-100\right)+4.3\frac{1}{2}\)
2)Tìm x:
a)\(\frac{1}{3}x-\left(-\frac{2}{3}\right)^2=\sqrt{\frac{16}{81}}\)
b)\(4x-\frac{2}{5}+\frac{3}{4}=\frac{11}{4}\)
3)So sánh hai số a và b biết \(a=8^{21}:2^{18}\)
\(b=6^{21}:2^{21}\)
2)
a) \(\frac{1}{3}x-\left(-\frac{2}{3}\right)^2=\sqrt{\frac{16}{81}}\)
\(\Rightarrow\frac{1}{3}x-\frac{4}{9}=\frac{4}{9}\)
\(\Rightarrow\frac{1}{3}x=\frac{4}{9}+\frac{4}{9}\)
\(\Rightarrow\frac{1}{3}x=\frac{8}{9}\)
\(\Rightarrow x=\frac{8}{9}:\frac{1}{3}\)
\(\Rightarrow x=\frac{8}{3}\)
Vậy \(x=\frac{8}{3}.\)
b) \(4x-\frac{2}{5}+\frac{3}{4}=\frac{11}{4}\)
\(\Rightarrow4x-\frac{2}{5}=\frac{11}{4}-\frac{3}{4}\)
\(\Rightarrow4x-\frac{2}{5}=2\)
\(\Rightarrow4x=2+\frac{2}{5}\)
\(\Rightarrow4x=\frac{12}{5}\)
\(\Rightarrow x=\frac{12}{5}:4\)
\(\Rightarrow x=\frac{3}{5}\)
Vậy \(x=\frac{3}{5}.\)
Chúc bạn học tốt!
