Question

решите на множестве R уравнение 7-6x-9x²=8

Answer 1

$7 - 6x - 9 {x}^{2} = 8 \ 7 - 6x - 9 {x}^{2} - 8 = 0 \ - 1 - 6x + 9 {x}^{2} = 0 \ 1 + 6x + 9 {x}^{2} = 0 \ 9 {x }^{2} + 6x + 1 = 0 \ (3x + 1) ^{2} = 0 \ 3x + 1 = 0 \ 3x = - 1 \ x = - frac{1}{3}$