Вправи: 572

572. Спростіть вираз:

1) (x – 12)² + 24x = x² – 24x + 144 + 24x = x² + 144;

2) (x + 8)² – x(x + 5)= x² + 16x + 64 – x² – 5x = 11x + 64;

3) 2x(x + 2) – (x – 2)² = 2x² + 4x – (x² – 4x + 4) = 2x² + 4x – x² + 4x – 4 = x² + 8x – 4;

4) (y + 7)² + (y + 2)(y – 7) = y² + 14y + 49 + y² – 7y + 2y – 14 =

= 2y² + 9y + 35;

5) (a + 1)(a – 1) – (a + 4)² = a² – 1 – (a² + 8a + 16) = a² – 1 – a² – 8a – 16 = –8a – 17;

6) (x – 10)(9 – x) + (x + 10)² = 9x – x² – 90 + 10x + x² + 20x + 100 = 39x + 10.