Bài 2:
` a) ` ` \frac{3.(-5)}{15.(-6)} = \frac{3.(-5)}{3.(-5).6} = 1/6 `
` b) ` ` \frac{-6.7}{-7.(-8)} = \frac{-2.3.7}{-2.4.(-7)} = \frac{-3}{4} `
` c) ` ` \frac{9.(-13)}{13.(-12)} = \frac{3.3.(-13)}{-13.3.4} = \frac{3}{4} `
` d) ` ` \frac{-21.(-5)}{15.(-7)} = \frac{3.(-7).(-5)}{3.5.(-7)} = -1 `
` e) ` ` \frac{32.9.11}{12.24.22} = \frac{4.2.2.2.3.3.11}{3.4.2.2.2.3.2.11} = \frac{1}{2} `
