<span>Sin(x+π/4)=1/2
x+</span>π/4=π/6+2πk U x+π/4=5π/6+2πk
x=-π/4+π/6+2πk U x=-π/4+5π/6+2πk
x=-π/12+2πk U x=7π/12+2πk,k∈z
(3х^2+у)(2у-5х^2)=6х^2у-15х^4+2у^2-5х^2у=х^2у-15х^4+2у^2
(7х-1)(х^2-4х+2)=7х^3-28х^2+14х-х^2+4х-2=7х^3-27х^2+18х-2
В первом ответ -7.5
Во втором -18/5 или -3 3/5