a_1=6, \ a_2=2\\*(12a-a^2-20)*(-1)=a^2-12a+20=0 => a_1=10,\ a_2=2\\-\frac{(a-6)(a-2)}{(a-10)(a-2)}=-\frac{a-6}{a-10} =\frac{6-a}{a-10}" alt="\frac{a^2-8a+12}{12a-a^2-20} \\* a^2-8a+12 => a_1=6, \ a_2=2\\*(12a-a^2-20)*(-1)=a^2-12a+20=0 => a_1=10,\ a_2=2\\-\frac{(a-6)(a-2)}{(a-10)(a-2)}=-\frac{a-6}{a-10} =\frac{6-a}{a-10}" align="absmiddle" class="latex-formula">