<span>3а²х² - 6а³х + 12а²х=</span>3а²х(х-2а+4)
7cos (2x-π/3) = -3.5|:7
cos (2x-π/3) = -1/2
2x-π/3=+-(π-arccos1/2)+2πn, n∈Z
2x-π/3=+-2π/3+2πn, n∈Z
2x=+-2π/3+π/3+2πn, n∈Z |:2
x=+-π/3+π/6+πn, n∈Z
x1=π/2+πn, n∈Z x2=-π/6+πn, n∈Z
2а`+4ас-3ас-6с`
2а`+ас-6с`
[вопшн `это квадрат]