в) log2$$\frac{8}{x}$$ - log2$$\sqrt{2x}$$ = -0,5
log2$$\frac{8}{x \cdot \sqrt{2x}}$$ = -0,5
$$\frac{8}{x \cdot \sqrt{2x}}$$ = 2-0,5 = $$\frac{1}{\sqrt{2}}$$
x$$\sqrt{2x}$$ = 8$$\sqrt{2}$$
x2 \cdot 2x = 64 \cdot 2
2x3 = 128
x3 = 64
x = 4
Проверка:
log2$$\frac{8}{4}$$ - log2$$\sqrt{2 \cdot 4}$$ = log22 - log2$$\sqrt{8}$$ = 1 - log22$$\sqrt{2}$$ = 1 - (1 + $$\frac{1}{2}$$) = -$$\frac{1}{2}$$ = -0,5
Ответ: 4