Question

помогите -21 x^2 +x+2 = 0

Answer 1

D = 1 + 168 = 169 = 13^2
X1 = ( - 1 + 13 ) : ( - 42 ) = - 12/42 = - 6/21 = - 2/7
X2 = ( - 1 - 13 ) : ( - 42 ) = 14/42 = 2/6 = 1/3
Ответ 1/3 ; - 2/7