Ответ:

а) (x - 3)² - x(x + 2,7) = 35,1

x² - 6x + 9 - x² - 2,7x = 35,1

-6x - 2,7x = 35,1 - 9

-8,7x = 26,1

x = 26,1 : (-8,7)

x = -3

б) (x + 7)² - (x - 4)(x + 4) = 65

x² + 14x + 49 - x² + 16 = 65

14x = 65 - 49 - 16

14x = 0

x = 0