28x-42-5x-20=23x-62
6x+10+5x=11x+10
23x-62=11x+10
12x=72
x=6
(ctgx+tgx)/(ctgx-tgx)=(1+tg^)/(1-tg^)=1/cos2x
14(2x-3)-5(x+4)=2(3x+5)+5x
14*2x-14*3-5x-5*4=2*3x+2*5+5x
28x-42-5x-20=6x+10+5x
28x-5x-5x-6x=42+20+10
12x=72
x=72:12
x=6
(ctgx+tgx)/(ctgx-tgx)=(1+tg^)/(1-tg^)=1/cos2x
