Помогите. очень важно..

11.
2,4·10⁻³ · 2·10⁻² = 4,8·10⁻⁵ = 0,000048 --- (Б)

12.
2x - 3(x + 4) < x + 12
2x - 3x - 12 < x + 12
-x - 12 < x + 12
2x > -24
x > -12 --- (A)

14.
nx² + 8x + 8 = 0
D = 64 - 32n
64 - 32n < 0
32n > 64
n > 2 --- (A)

15.
$\frac{x^2-3}{x^2-x} - \frac{x}{x-1} =\frac{x^2-3}{x(x-1)} - \frac{x}{x-1}=\frac{x^2-3-x^2}{x(x-1)}=-\frac{3}{x^2-x}$ --- (A)