Hướng dẫn trả lời:
Bài 1:
a) `1/x.{6x}/y.`
`= {1.6x}/{x.y}.`
`= {1.6}/{y}.`
`= {6}/{y}.`
b) `{15x}/{7y^3}.{-2y^2}/{x^2}.`
`= {15x.(-2y^2)}/{7y^3.x^2}.`
`= {15.x.(-2).y^2}/{7y.y^2.x.x}.`
`= {15.(-2)}/{7y.x}.`
`= {-30}/{7xy}.`
c) `{25x^3y^5}/3 ÷ 15xy^2.`
`= {25x^3y^5}/3. 1/{15xy^2}.`
`= {25x^3y^5 .1}/{3.15xy^2}.`
`= {5x^2y^3. 5xy^2 .1}/{3.3.5xy^2}.`
`= {5x^2y^3 .1}/{3.3}.`
`= {5x^2y^3}/{9}.`
d) `{2x^2}/{x - y}.{y}/{5x^2}.`
`= {2x^2.y}/{(x - y).5x^2}.`
`= {2.x^2.y}/{(x - y).5.x^2}.`
`= {2.y}/{5.(x - y)}.`
`= {2y}/{5(x - y)}.`
e) `{x^2 - 36}/[2x + 10}.{3}/{6 - x}.`
`= {x^2 - 6^2}/2.{x + 5}.{3}/{-(x - 6)}.`
`= {(x^2 - 6^2) .3}/{2.(x + 5).-(x - 6)}.`
`= {(x + 6).(x - 6).3}/{(2.(x + 5).-(x - 6)}.`
`= - {3(x + 6)}/{2.(x + 5)}.`
f) `{x^2 - 9y^2}/{x^2y^2}.{3xy}/{2x - 6y}.`
`= {x^2 - (3y)^2}/{x^2y^2}.{3xy}/{2.(x - 3y)}.`
`= {(x + 3y).(x - 3y).3.xy}/{xy.xy.2.(x - 3y)}.`
`= {3.(x + 3y)}/{2xy}.`
