a) (5+2х)(2х-5)+25
б) 4(7-2a)-(a-4)[tex]{2}[/tex] с

1. (5+2x)(2x-5) + 25 = (2x+5)(2x-5) + 25 = 4x² - 25 + 25 = 4x²

2. 4(7-2a) - (a-4)² = 28 - 8a - a² + 8a - 16 = 12 - a²