х^3+125-х^3-3х=125-3х, 125- 3(-2)=125+6=131
а^2+2ав+в^2+а^2-2ав+в^2=2(а^2+в^2)
а^2+в^2+а^2+в^2=2(а^2+в^2)
2(а^2+в^2)=2(а^2+в^2)
х^3+125-х^3-3х=125-3х, 125- 3(-2)=125+6=131
а^2+2ав+в^2+а^2-2ав+в^2=2(а^2+в^2)
а^2+в^2+а^2+в^2=2(а^2+в^2)
2(а^2+в^2)=2(а^2+в^2)