Question

Сократите дробь: 2)15b-20c 10b 4)a-3b a^2+3ab 6) 3x^2+15xy x+5y 8)5x-15y x^2-9y^2 10)6cb-18c^2 (b-c)^3 12)a^3-b^3 a-b

Answer 1

$\frac{5(3b - 4c)}{10b} = \frac{3b - 4c}{2b}; \frac{a - 3b}{ a^{2} + 3ab } = \frac{a-3b}{a(a+3b)}= \frac{1}{a}; \frac{3 x^{2} + 15xy}{x+5y} = \frac{3x(x+5y)}{x+5y} = 3x;$$\frac{5x-15y}{ x^{2} -9 y^{2} } = \frac{5(x-3y)}{(x+3y)(x-3y)} = \frac{5}{x+3y}$$;\frac{6cb-18 c^{2} }{(bc)^{3} } = \frac{6c(b-3c)}{ b^{3} c^{3} } = \frac{6(b-3c)}{ b^{3} c^{2} } ;$$\frac{a^{3}- b^{3} }{a - b} = \frac{ (a-b)^{3} }{a-b} = (a-b)^{2} = a^{2} - b^{2} .$