=49x^2 - 1 -49x^2 + 6x - 2 = 6x - 3 = 6*110 - 3 = 660 - 3 = 657 Ответ 657
Рассмотрим треуголиник SOD. SO=12 OD=1/2BD=9 SOD=90 12^2=9^2+SD 144=81+SD SD=sqrt63 SD=SA
2x^2+3x = 2x^2+21
3x = 21
x = 7
(3x+1)(4x-5) = 12x^2-13x+1
12x^2-11x-5 = 12x^2-13x+1
2x = 6
x = 3
(2x-3)(3x+7)-(x-5) = 12x^2-13x+1
6x^2+14x-9x-21-x+5 = 12x^2-13x+1
-6x^2+17x = 17
x(17-6x) = 17
6x+15+6-3=0
6x+18=0
6x=-18
x=-3
………=ab(ab -1)+1
при а=1/2 b
1/2b*b(1/2b*b -1)=1/2(1/2-1)=1/2*1/2=1/4