Теорема Виета: х1*х2= с/а х1+х2=-b/a примечание: решается так если Х² это единица. то есть не 2х² не 3х² и т.д. Через Дискриминанд D=b²-4ac x1,2= -b±√D/2a(деление-знак дробью писать)
дальше есть разные другие формулы быстрого решения. такие как ах²+bх+ с=0 1° а+b+c=0 х1=1 х2= с/а (это применяется в случае если при сложение коэффициентов получается ноль. От знака не зависит. Не важно какой знак перед числом, главное чтобы в итоге было 0. пример: 2х²+3х-5= 0 2+3-5=0 значит х1=1. х2= 2,5
1. Lena didn't want to get up,did she? Yes, Lena didn't want to get up. 2. Lena had a lot to do, didn't she ? Yes she did. Lena had a lot to do. 3. It was windy and cold outside, wasn't it? Yes it was. It was windy and cold outside. 4. Lena couldn't think about the party and the cake, could she? Yes she couldn't think about the party and the cake. 5. Lena and her mother decided to have lemon tea and sandwiches for breakfast, didn't they ? Yes they did. They decided to have lemon tea and sandwiches for breakfast. 6 Lena was happy to stay in bed, wasn't she? Yes, she was. She was happy to stay in bed.
