a, Đặt \(\frac{a}{b}=\frac{c}{d}=k\Rightarrow a=b.k,c=d.k\)
+) \(\frac{5a+3b}{5a-3b}=\frac{5.b.k+3.b}{5.b.k-3.b}=\frac{b.\left(5k+3\right)}{b.\left(5k-3\right)}=\frac{5k+3}{5k-3}\left(1\right)\)
+) \(\frac{5c+3d}{5c-3d}=\frac{5.d.k+3.d}{5.d.k-3.d}=\frac{d.\left(5k+3\right)}{d.\left(5k-3\right)}=\frac{5k+3}{5k-3}\left(2\right)\)
Từ (1) và(2) => ĐPCM
b, Đặt \(\frac{a}{b}=\frac{c}{d}=k\Rightarrow a=b.k,c=d.k\)
+) \(\frac{7a^2+3ab}{11a^2-8ab^2}=\frac{7k^2.b^2+3kb^2}{11k^2.b^2-8b^2}=\frac{7k^2+3k}{11k^2-8}\left(1\right)\)
+) \(\frac{7c^2+3cd}{11c^2-8d^2}=\frac{7k^2.d^2+3k.d^2}{11k^2.d^2-8d^2}=\frac{7k^2+3k}{11k^2-8}\left(2\right)\)
Từ (1) và (2) => ĐPCM
Tính:
A=\(\left(1-\frac{2}{3}+\frac{4}{3}\right)-\left(\frac{4}{5}-1\right)+\left(\frac{7}{5}+2\right)\)
B=\(\left(-3+\frac{3}{4}-\frac{1}{3}\right):\left(5+\frac{2}{5}-\frac{2}{3}\right)\)
C=\(\left(\frac{3}{5}-\frac{4}{15}\right).\left(\frac{2}{7}-\frac{3}{14}\right)-\left(\frac{5}{9}-\frac{7}{27}\right)\)\(.\left(1-\frac{3}{5}\right)+\left(1-\frac{11}{12}\right).\left(1+\frac{11}{12}\right)\)
D=\(\frac{\left(\frac{3}{10}-\frac{4}{15}-\frac{7}{20}\right).\frac{-5}{19}}{\left(\frac{1}{14}+\frac{1}{7}-\frac{-3}{35}\right).\frac{4}{3}}\)
1 tính
a, \(\left(\frac{1}{2}\right)^4\)
b, \(\left(\frac{1}{2}\right)^3\)
c, \(\left(\frac{-3}{5}\right)^2\)
d, \(\left(\frac{-1}{5}\right)^2\)
e, \(\left(\frac{-1}{6}\right)^3\)
2 tính
a, \(\left(\frac{3}{2}\right)^2.\left(\frac{4}{3}\right)^2\)
b,\(\left(\frac{-1}{2}\right)^3.\left(\frac{2}{3}\right)^3\)
c, \(\left(\frac{-1}{2}\right)^2.\left(\frac{2}{5}\right)^2\)
d, \(\left(\frac{-1}{2}\right)^3.\left(\frac{2}{3}\right)^3\)
e, ( -5 ) 3 x \(\left(\frac{1}{5}\right)\)
f, \(\left(\frac{2}{9}\right)^5.\left(\frac{-27}{4}\right)^5\)
Bài 1: Thực hiện phép tính
a) \(2^3+3.\left(\frac{1}{2}\right)^0+\left[\left(-2\right)^2:\frac{1}{2}\right]\)
b) \(\frac{2^{15}.9^4}{6^6.8^3}\)
c) \(\left(1+\frac{2}{3}-\frac{1}{4}\right).\left(\frac{4}{5}-\frac{3}{4}\right)^2\)
d) \(\left(\frac{-10}{3}\right)^3.\left(\frac{-6}{5}\right)^4\)
tính giá trị biểu thức
a, A=\(\frac{-1}{2}-\left[\frac{-3}{5}\right]+\left[\frac{-1}{9}\right]+\frac{1}{27}+\frac{7}{18}+\frac{4}{35}-\left[-\frac{2}{7}\right]\)
b, B=\(\frac{1}{3}-\frac{3}{4}-\left[\frac{-3}{5}-\frac{1}{57}+\frac{1}{36}+\frac{-1}{15}\right]-\frac{2}{9}\)
c, C=\(\left[-\frac{7}{15}\right]\times\frac{5}{8}\times\left[\frac{30}{-7}\right]\times\left[-16\right]\times\left[\frac{-1}{1000}\right]\)
d, D=\(\frac{1}{2}\times\frac{-11}{19}-50\%\times\left[-\frac{1}{19}\right]+\frac{10}{19}\times\frac{1111}{2222}\)
a,\(\left\{\frac{2}{3}\right\}^3-\left\{\frac{3}{4}\right\}^2.\left\{-1\right\}^5\)
b,\(12:\left\{\frac{3}{4}-\frac{5}{6}\right\}^2\)
c,\(\frac{7}{22}:\frac{3}{11}+\frac{7}{22}:\frac{4}{11}\)
d,\(\frac{12}{35}.\left\{\frac{7}{4}+\frac{13}{4}\right\}-\frac{1}{3}\)
Tìm x :
a) \(3x\left(x-\frac{2}{5}\right)=0\)
b)\(\frac{2}{3}:x=2\frac{1}{2}:\left(-0,3\right)\)
c)\(\frac{11}{13}-\left(\frac{5}{42}-x\right)=-\left(\frac{15}{28}-\frac{11}{13}\right)\)
d) \(\left|\frac{2}{3}.x-\frac{2}{3}\right|-\frac{2}{3}=\left|-\frac{2}{3}\right|\)
1 tính
a \(\left(\frac{9}{14}-\frac{9}{21}\right):\left(\frac{4}{5}+\frac{5}{6}\right)\)
b \(\frac{7}{10}-\frac{-3}{4}+\frac{-5}{6}-\frac{1}{5}+\frac{-2}{3}\)
c \(\left(-2\right)^2.\left(\frac{3}{4}-0,25\right):\left(2\frac{1}{4}-1\frac{1}{6}\right)\)
d \(-\frac{1}{7}.\left(9\frac{1}{2}-0,75\right):\frac{2}{7}+0,625:1\frac{2}{3}\)
Rút gọn:
a,\(\left(\frac{2}{3}\right)^3\):\(\left(\frac{-1}{3}\right)^5\)b,\(\left(\frac{5}{7}\right)^6\):\(\left(-\frac{25}{49^{ }}\right)^3\)
c,\(\left(-\frac{2}{9}\right)^4\).\(\left(\frac{27}{16}\right)^7\)d,\(\left(\frac{1}{3}\right)^6\).\(\left(-\frac{21}{19}\right)^3\)
