30х^2-17х-35 = 0
D = b^{2} - 4*a*c
D = 289 + 4200 = 4489
x1,2 = -b+-sqrt(D)/2a
x1 = 17+67/2*30 = 1,4
x2 = 17-67/2*30 = -5/6
Ответ: -5/6 ; 1,4
176/220=88/110=44/55=4/5=0,8=80\%