Не знаю правильно или нет
8+7=15
8-7=1
а)
(с-3)(с+3)=с²-9
б)
(7х-у)(7х+у)=49х²-у²
в)
(-3а+b²)(b²+3а)=(b²-3а)(b²+3а)=b^4-9а²
Cos(π/4 - x) > √3/2
cos(x - π/4) > √3/2
- arccos(√3/2) + 2πn < x - π/4 < arccos(√3/2) + 2πn, n∈z
- π/6 + 2πn < x - π/4 < π/6 + 2πn, n∈Z
- π/6 + π/4 + 2πn < x < π/6 + π/4 + 2πn, n∈Z
π/12 + 2πn < x < (5π)/12 + 2πn, n∈Z