Question

помогите с первым
пожалуйста

Answer 1

$= 7x {}^{2} - x = 0 \ x(7x - 1) = 0 \ x = 0 \ x = frac{1}{7} \ (6 - 2x) {}^{2} = 3x - 9 \ 36 - 24x + 4x {}^{2} = 3x - 9 \ 4x {}^{2} - 27x + 45 = 0 \ d = 27 {}^{2} - 16 times 45 = 9 \ x1 = frac{27 + 9}{8} = frac{36}{8} = frac{9}{2} \ x2 = frac{27 - 9}{8} = frac{18}{8} = frac{9}{4} \ \ 2 {x}^{3} - 8x {}^{2} + 5x - 20 = 0 \ 2x {}^{2} (x - 4) + 5(x - 4) \ (x - 4)(2x {}^{2} + 5) = 0 \ x1 = 4 \ 2x {}^{2} + 5 = 0$