Bai 1: \(\left(-2\right)^3.\left(\dfrac{3}{4}-0,25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=\left(-8\right).\left(\dfrac{3}{4}-\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)
\(=\left(-8\right).\dfrac{1}{2}:\left(\dfrac{27}{12}-\dfrac{14}{12}\right)\)
\(=\left(-4\right):\dfrac{13}{12}\)
\(=\left(-4\right).\dfrac{12}{13}\)
\(=\dfrac{-48}{13}\)
Bai 2:
\(a,4\dfrac{1}{3}:\dfrac{x}{4}=6:0,3\)
\(\dfrac{13}{3}:\dfrac{x}{4}=20\)
\(\dfrac{x}{4}=\dfrac{13}{3}:20\)
\(\dfrac{x}{4}=\dfrac{13}{60}\)
➩ \(x.60=4.13\) ➩ \(x.60=52\) ➩ \(x=\dfrac{13}{15}\)
Vay \(x=\dfrac{13}{15}\)
\(b,\left(2^3:4\right).2^{\left(x+1\right)}=64\)
\(\left(8:4\right).2^{x+1}=64\)
\(2.2^{x+1}=64\)
\(2^{x+1}=32\)
➩ \(2^{x+1}=2^5\) ➩ \(x+1=5\) ➩ \(x=4\)
Vay \(x=4\)
