X-y = 12 => y = x-12
x^2 - y^2 = 44
x^2 - (x-12)^2 = 44
x^2 - (x^2 - 24x + 144) = 44
24x - 144 = 44
24x = 188
x = 188/24 = 94/12 = 47/6
y = x - 12 = 47/6 - 12 = 47/6 - 72/6 = - 25/6
ответ: 25/6 (двадцать пять шестых)
Sin135°=sin(90°+45°)=cos45°=√2/2
cos210°=cos(180°+30°)= -cos30°= -√3/2
tg240°=tg(180°+60°)=tg60°=√3
ctg300°=ctg(270°+30°)= -tg30°= -√3/3
√2/2*(-√3/2)*(-3)=3√6/4