Question

[36] Упростите выражение:
х^2 - (9-x)^2 >-2х​

Answer 1

$x {}^{2} - (9 - x) {}^{2} + 2x > 0 \\ x {}^{2} - 81 + 18x - x {}^{2} + 2x > 0 \\ - 81 + 18x + 2x > 0 \\ - 81 + 20x > 0 \\ 20x > 81 \\ x > \frac{81}{20}$

$otvet \\ x > \frac{81}{20} \\ \\ ( \frac{81}{20} . \infty )$