Решите уравнение а)5/8х^2=6х-25 б)7х^2-50х+7=0 в)х^2(х-1)(х+1)/5=7х^2+32/3

Question

Алгебра: Решите уравнение а)5/8х^2=6х-25 б)7х^2-50х+7=0 в)х^2(х-1)(х+1)/5=7х^2+32/3

mintbouquet · Accepted Answer

B1 + b1q^3 = -49
b1q + b1q^2 = 14 разделим первое уравнение на 2-е
(1 + q^3)/(q +q^2) = -7/2
(1+q)(1 -q +q^2)/q(1 +q) = -7/2
(1 -q +q^2) /q = -7/2
2(1 - q +q^2) = -7q
2 -2q +2q^2 +7q = 0
2q^2 +5q +2 = 0
D = b^2 -4ac = 25 -16 = 9
q1= -1/2, a) b1 + b1q^3 = -49    б) q2 =-2     b1 + b1q^3 = -49
b1 +b1*(-1/8) = -49    b1 + b1*(-8) = -49
7/8 b1 = -49    -7b1 = -49
b1 = -49: 7/8= -49*8/7= =56    b1 = 7

MOGZ ответил