[tex]\displaystyle 1)\frac{4x^2-11x-3}{-3x^2+10x-3}=\frac{4x^2+x-12x-3}{-3x^2+9x+x-3}=\frac{x(4x+1)-3(4x+1)}{-3x(x-3)+x-3}=\frac{(4x+1)(x-3)}{(x-3)(-3x+1)}=\\\frac{4x+1}{-3x+1} \\ \\2)\frac{2x+10}{x^2+x-20}=\frac{2(x+5)}{x^2+5x-4x-20}=\frac{2(x+5)}{x(x+5)-4(x+50}=\frac{2(x+5)}{(x+5)(x-4)}=\\\frac{2}{x-4}\\ \\3)\frac{3x^2+7x-6}{4-9x^2}=\frac{3x^2+9x-2x-6}{(2-3x)(2+3x)}=\frac{3x(x+3)-2(x+3)}{-(3x-2)(2+3x)}=\frac{(x+3)(3x-2)}{-(3x-2)(2+3x)}=\\\frac{(x+3)(-1)}{2+3x}=-\frac{x+3}{2+3x}[/tex]