**28.35**
* **a)** \((a - 4)^2 + a(a + 8) = (a^2 - 8a + 16) + (a^2 + 8a) = 2a^2 + 16\)
* **б)** \((x - 7)x + (x + 3)^2 = (x^2 - 7x) + (x^2 + 6x + 9) = 2x^2 - x + 9\)
* **в)** \((y - 5)^2 - (y - 2) = (y^2 - 10y + 25) - (y - 2) = y^2 - 11y + 27\)
* **г)** \(b(b + 4) - (b + 2)^2 = (b^2 + 4b) - (b^2 + 4b + 4) = -4\)