Ответ:

1) \(9c^2-16=(3c-4)(3c+4)\), \(16-24c+9c^2=(3c-4)^2\).

\(\frac{9c^2-16}{16-24c+9c^2}=\frac{3c+4}{3c-4}\).

2) \(16x^2-24xy+9y^2=(4x-3y)^2\), \(9y^2-16x^2=-(4x-3y)(4x+3y)\).

\(\frac{16x^2-24xy+9y^2}{9y^2-16x^2}=-\frac{4x-3y}{4x+3y}=\frac{3y-4x}{4x+3y}\).

3) \(4x^2-4xy+y^2=(2x-y)^2\), \(y^2-4x^2=-(2x-y)(2x+y)\).

\(\frac{4x^2-4xy+y^2}{y^2-4x^2}=\frac{y-2x}{y+2x}\).

4) \(36c-c^3=c(6-c)(6+c)\), \(c^3+12c^2+36c=c(c+6)^2\).

\(\frac{36c-c^3}{c^3+12c^2+36c}=\frac{6-c}{c+6}\).

5) \(25b-49b^3=b(5-7b)(5+7b)\), \(49b^3-70b^2+25b=b(7b-5)^2=b(5-7b)^2\).

\(\frac{25b-49b^3}{49b^3-70b^2+25b}=\frac{5+7b}{5-7b}\).

6) \(4b^2-12bc+9c^2=(2b-3c)^2\), \(-2ab+3ac=-a(2b-3c)\).

\(\frac{4b^2-12bc+9c^2}{-2ab+3ac}=\frac{3c-2b}{a}\).

Ответ: 1) \(\frac{3c+4}{3c-4}\); 2) \(\frac{3y-4x}{4x+3y}\); 3) \(\frac{y-2x}{y+2x}\); 4) \(\frac{6-c}{c+6}\); 5) \(\frac{5+7b}{5-7b}\); 6) \(\frac{3c-2b}{a}\).