Tính nhanh (nếu có thể): \(\left(\frac{1}{9}\right)^{15}:\left(\frac{1}{3}\right)^{30}\)
BÀi 1: Thực hiện phép tính ( tính nhanh nếu có thể)
a.\(\left(-\frac{1}{2}\right)-\left(-\frac{3}{5}\right)+\left(-\frac{1}{9}\right)+\frac{1}{71}-\left(-\frac{2}{7}\right)+\frac{4}{35}-\frac{7}{18}\)
b.\(\left(3-\frac{1}{4}+\frac{2}{3}\right)-\left(5-\frac{1}{3}-\frac{6}{5}\right)-\left(6-\frac{7}{4}+\frac{3}{2}\right)\)
c.\(\frac{3}{5}:\left(\frac{-1}{15}-\frac{1}{6}\right)+\frac{3}{5}:\left(\frac{1}{3}-1\frac{1}{15}\right)\)
Tính nhanh biểu thức sau (nếu có thể):
\(\frac{5}{9}:\left(\frac{1}{11}-\frac{5}{22}\right)+\frac{5}{9}:\left(\frac{1}{15}-\frac{2}{3}\right)\)
\(=\frac{5}{9}:\left(-\frac{3}{22}\right)+\frac{5}{9}:\left(-\frac{3}{5}\right)\)
\(=\frac{5}{9}.\left[\left(-\frac{22}{3}\right)+\left(-\frac{5}{3}\right)\right]\)
\(=\frac{5}{9}.\left(-9\right)=-5\)
1,Tính : ( Hãy tính nhanh nếu có thể )
a,\(\frac{3^6.45^4-15^{13}.\left(\frac{1}{5}\right)^9}{27^4.25^3+45^6}\)
b,\(\frac{\left(\frac{2}{5}\right)^7.5^7+\left(\frac{9}{4}\right)^3:\left(\frac{3}{16}\right)^3}{2^7.5^2+512}\)
tính nhanh nếu có thể
\(\left(-\frac{1}{2}\right)-\left(-\frac{3}{5}\right)+\left(-\frac{1}{9}\right)+\frac{1}{71}-\left(-\frac{2}{7}\right)+\frac{4}{35}-\frac{7}{18}\)
tính nhanh nếu có thể
\(\left(-\frac{1}{2}\right)-\left(-\frac{3}{5}\right)+\left(-\frac{1}{9}\right)+\frac{1}{71}-\left(-\frac{2}{7}\right)+\frac{4}{35}-\frac{7}{18}\)
\(\left(\frac{-1}{2}\right)\)+ \(\left(\frac{-1}{9}\right)\)\(-\frac{7}{18}\)\(-\left(-\frac{3}{5}\right)\)\(-\left(-\frac{2}{7}\right)\)\(+\frac{4}{35}\)+ \(\frac{1}{71}\)
=\(\frac{-9-2-7}{18}\)\(-\frac{-21-10-4}{35}\)+\(\frac{1}{71}\)
=\(\frac{-18}{18}\)\(-\frac{-35}{35}\)+\(\frac{1}{71}\)
=-1 -(-1)+\(\frac{1}{71}\)
=\(\frac{1}{71}\)
Thực hiện phép tính : (Tính nhanh nếu có thể)
(\(\left(5+\frac{1}{5}-\frac{2}{9}\right)-\left(2-\frac{1}{23}-2\frac{3}{5}+\frac{5}{6}\right)-\left(8-\frac{2}{3}-\frac{1}{18}\right)\)
Theo đề ta có:
\(\left(5+\frac{1}{5}-\frac{2}{9}\right)-\left(2-\frac{1}{23}-2\frac{3}{5}+\frac{5}{6}\right)\)\(-\left(8-\frac{2}{3}-\frac{1}{18}\right)\)
= \(5+\)\(\frac{1}{5}-\frac{2}{9}\)-\(2+\frac{1}{23}+2+\frac{3}{5}+\frac{5}{6}-8+\frac{2}{3}-\frac{1}{18}\)
=\(\left(5+2-8\right)+\left(\frac{1}{5}+\frac{3}{5}\right)-\left(\frac{2}{9}-\frac{5}{6}-\frac{2}{3}+\frac{1}{18}\right)+\frac{1}{23}\)
= -1 +\(\frac{4}{5}\)\(-\frac{-11}{9}\)+\(\frac{1}{23}\)
= -1 +\(\frac{4}{5}+\frac{11}{9}+\frac{1}{23}\)
\(\left(5+\frac{1}{5}-\frac{2}{9}\right)-\left(2-\frac{1}{23}-2\frac{3}{5}+\frac{5}{6}\right)-\left(8-\frac{2}{3}-\frac{1}{18}\right)\)
= \(5+\frac{1}{5}-\frac{2}{9}-2+\frac{1}{23}+2+\frac{3}{5}-\frac{5}{6}-8+\frac{2}{3}+\frac{1}{18}\)
= \(\left(5-8\right)+\left(\frac{1}{5}+\frac{3}{5}\right)-\left(\frac{2}{9}-\frac{1}{18}-\frac{2}{3}\right)-\left(2-2\right)+\frac{1}{23}-\frac{5}{6}\)
= \(\left(-3\right)+\frac{4}{5}+\frac{1}{2}+\frac{1}{23}-\frac{5}{6}\)
= \(\left(\left(-3\right)+\frac{4}{5}+\frac{1}{2}-\frac{5}{6}\right)+\frac{1}{23}\)
= \(-\frac{38}{15}+\frac{1}{23}\)
= \(-\frac{859}{345}\)
1.Tính nhanh(nếu có thể) :
a) \(\left(\frac{3}{7}\right)^{21}:\left(\frac{9}{49}\right)^6\)
b)\(3-\left(-\frac{6}{7}\right)^0+\left(\frac{1}{2}\right)^2:2\)
k nha
thực hiện phép tính : ( tính nhanh nếu có thể )
a) \(\left(\frac{11}{12}:\frac{33}{16}\right).\frac{3}{5}+\frac{7}{23}.\left[\left(\frac{-8}{6}+\frac{-45}{18}\right)\right]\)
b) \(\left(\frac{-2}{3}+\frac{3}{7}\right):\frac{4}{5}+\left(\frac{-1}{3}+\frac{4}{7}\right):\frac{4}{5}\)
c) \(\frac{5}{9}:\left(\frac{1}{11}-\frac{5}{22}\right)+\frac{5}{9}:\left(\frac{1}{15}-\frac{2}{3}\right)\)
d) \(\frac{-3}{4}.\frac{12}{-5}.\frac{-25}{6}+\left(-2\right).\frac{-38}{21}.\frac{-7}{4}.\frac{-3}{8}\)
Bài 1 : tìm x, biết
a) \(\left(\frac{1}{4}-x\right)\left(x+\frac{2}{5}\right)=0\)
bài 2 : Thực hiện các phép tính sau bằng cách hợp lí nếu có thể :
a) \(\left(\frac{13}{24}-\frac{29}{30}\right):\left(\frac{-51}{5}\right)\)
bài 3 : tính nhanh
A = \(\frac{1}{3}-\frac{3}{4}-\left(\frac{-3}{5}\right)+\frac{1}{72}-\frac{2}{9}-\frac{1}{36}+\frac{1}{15}\)
B = \(\frac{1}{5}-\frac{3}{7}+\frac{5}{9}-\frac{2}{11}+\frac{7}{13}-\frac{9}{16}-\frac{7}{13}+\frac{2}{11}-\frac{5}{9}+\frac{3}{7}-\frac{1}{5}\)
C = \(\frac{1}{100}-\frac{1}{100.99}-\frac{1}{99.98}-\frac{1}{98.97}-....-\frac{1}{3.2}-\frac{1}{2.1}\)
\(\left(\frac{1}{4}-x\right)\left(x+\frac{2}{5}\right)=0\)
Ta xét 2 trường hợp
\(\begin{cases}\frac{1}{4}-x=0\\x+\frac{2}{5}=0\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{1}{4}\\x=-\frac{2}{5}\end{cases}}\)
tớ mới làm bài 1 thôi bài 2 3 tớ ko có thời gian
Bài 1: Tìm x, biết:
\(\left(\frac{1}{4}-x\right)\left(x+\frac{2}{5}\right)=0\)
\(\Rightarrow\hept{\begin{cases}\frac{1}{4}-x=0\\x+\frac{2}{5}=0\end{cases}\Rightarrow\hept{\begin{cases}x=\frac{1}{4}\\x=-\frac{2}{5}\end{cases}}}\)