ctg(2(П/4+x))=ctg(П/2+2x)=tg2x cosx=sqrt(1-15^2/17^2)=-8/17
sin2x=2*8/17*15/17=240/289
cos2x=64/289-225/289=-161/289
tg2x=240/161 [П;5/4П]
tg2x=-240/161 [5/4П/3П/2]
4х=-8+3у
х=-(8+3у):4
-3(8+3у):4-4у=-13
(-24+3у):4+13=4у
4у=(28+3у):4
13у=28
у=28:13
Y=1.5x-12=1.5*6.4-12=9.6-12=-2.4