11)
lg((x-5)/(x-2)) = 2
lg((x-5)/(x-2)) = lg 100
(x-5)/(x-2) = 100
(x-5)/(x-2) - 100 = 0
x-5 - 100(x-2) = 0 ОДЗ: х - 2≠0, (х-5)/(х-2)>0
х - 5 - 100х+2 = 0 х≠2 x∈ (-∞; 2)∪(5; +∞)
-99х = 3
х = -1/33
12.
2cos x = √2
cos x = √2/2
x = +/- π/4+2πk
13. Надо построить ветвь параболы по точкам
(0;0), (1; -1/3), (4; -2/3), (9; -1), (16; -4/3)