Question

Помогите пожалуйста! 30баллов

Answer 1

1) 0.7(1-3x)^2=0

(1-3x)^2=0

1-3x=0

-3x=-1

x=1/3

ответ 1/3

2)

Объяснение:

$( \frac{1 + x {}^{2} }{x} ) {}^{2} + \frac{3}{x {}^{2} } = \frac{(1 + x {}^{2}) {}^{2} }{x {}^{2} } + \frac{3}{x {}^{2} } = \frac{1 + 2x {}^{2} + {x}^{4} + 3}{x {}^{2} } = \frac{ {x}^{4} + 2x {}^{2} + 4}{x {}^{2} }$

$\frac{ {2}^{4} + 2 \times 2 {}^{2} + 4 }{2 {}^{2} } = 7$

3)

$x {}^{2} - 4x + 4 = x {}^{2} + 4x - 5x - 20$

$- 4x + 4 = 4x - 5x - 20$

$- 4x + x = - x - 20$

$- 3x = - 24$

$x = 8$