Question

Решите 5 и 7 и из 17 3
Пожалуйста

Answer 1

5)
$x - {11x}^{2} = 0 \ x(1 - 11x) = 0 \ x = 0 : u : 1 - 11x = 0 \ - 11x = - 1 \ x = frac{ - 1}{ - 11} \ x = frac{1}{11}$
х = 0 и х = 1/11.

7)
${2n}^{2} = 7n + 9 \ {2n}^{2} - 7n - 9 = 0$
a=2, b=-7, c=-9.
т.к. b=a+c, то х=-1; х=-с/а=9/2=4,5.

3)
${9x}^{2} + 6 = 21x \ {9x}^{2} - 21x + 6 = 0 \ {3x}^{2} - 7x + 2 = 0 \ {3x}^{2} - x - 6x + 2 = 0 \ x(3x - 1) - 2(3x - 1) = 0 \ (x - 2)(3x - 1) = 0 \ x - 2 = 0 : u : 3x - 1 = 0 \x = 2 : u : x = frac{1}{ 3}$
х=2 и х=1/3.