решите уравнения 50 Баллов
1) 5x^2+4x-1=0
2) 16x^2-2x-5=0
3)28x^2-36x+11=0
4) -49x^2+21x-2=0

1. D=16+20=36.x1,2=-4±√36 / 10.x1=-4+6 / 10 = 0,2.x2=-4-6 / 10 = -1.2. D=4+320=324.x1,2=2±√324 / 32.x1=2+18 / 32 = ⅝.x2=2-18 / 32 = -½.3. D=1296-1232=64.x1,2=36±√64 / 56.x1=36+8 / 56 = 11/14.x2=36-8 / 56 = ½.4. D=441-392=49.x1,2=-21±√49 / -98.x1=-21+7 / -98 = 1/7.x2=-21-7 / -98 = 14/49.