Question

Розв'яжіть функції!!!! 10балів

Answer 1

1)

$\sqrt{x + 2} - x = 0 \\ \sqrt{x + 2} = x \\ x + 2 = x {}^{2} \\ - x {}^{2} + x + 2 = 0 \\ d = 1 - 4 \times ( - 1) \times 2 = 9 \\ x1 = 2 \\ x2 = - 1$

2)

$x {}^{3} - 3x {}^{2} + x - 3 = 0 \\ x {}^{2} (x - 3) - (x - 3) = 0 \\ - (x - 3) \times (x {}^{2} + 1) = 0 \\ - (x - 3) = 0 \\ x = 3 \\ x { }^{2} + 1 = 0 \\ x {}^{2} = -1$

3)

$- |x - 2| = - 1 \\ |x - 2| = 1 \\ x - 2 = 1 \\ x - 2 = - 1 \\ x = 3 \\ x = 1$

4)

$\frac{x {}^{2} - 2x - 15}{x + 3} \\ \frac{x(x + 3) - 5(x + 3)}{x + 3} \\ \frac{(x + 3)(x - 5)}{x + 3} \\ x - 5 = 0 \\ x = 5$