Вправи: 629

629. Розкрийте дужки та спростіть вираз:

1) p(p – 15) = p – 15p;

2) n(2n + 5) = 2n + 5n;

3) 3(a + c) = 3a + 3c;

4) (n + 7)( n – 2) = n – 2n + 7n – 14 = n + 5n – 14;

5) (2x + y)( x – 2y) = 2x – 4xy + xy – 2y = 2x – 3xy – 2y;

6) (a + 1)( a – 1) = (a)² – 1² = a – 1;

7) (x + y)(y – x) = (y + x)( y – x) = (y)² – (x)² = y – x;

8) (a + a)( a – a) = (a)² – a² = a – a²;

9) (5m + n)( 5m – n) = (5m)² – (n)² = 5m – n;

10) (x + 1)² = (x)² + 2x • 1 + 1² = x + 2x + 1;

11) (a – 4)² = (a)² – 2 • a • 4 + 4² = a – 8a + 16;

12) (m + 3)² = (m)² + 2 • m • 3 + (3)² = m + 23m + 3;

13) (x – 2y)² = (x)² – 2 • x • 2y + (2y)² = x – 22xy + 2y;

14) (x + z)² = (x)² + 2x • z + (z)² = x + 2xz + z.