1/(4а-+1)-1/(4а-1)=(4а-1-(4а+1))/(16а²-1)=(4а-1-4а-1)/(16а²-1)=-2/(16а²-1)

(16а²-1)·(-2/(16а²-1)=-2,  Ответ:-2

2).(х²-12х+10)/(1-6х)≤1,(х²-12х+10)/(1-6х)-1≤0, (х²-12х+10-(1-6х))/(1-6х)≤0,  

(х²-12х+10-1+6х)/(1-6х)≤0, (х²-6х+9)/(1-6х)≤0,или (х²-6х+9)·(1-6х)≤0

6(х-3)²·(х-1/6)≥0 ,х≠1/6  или (х-3)²·(х-1/6)≥0,х≠1/6 отсюда х>1/6