1.

а) - 2 • 3^2 + 6^2 = - 2 • 9 + 36 = 18;

б) - 5,6 : 1 1/7 = - 56/10 : 8/7 = - 6,4.

2.

а) 27b^4 / 9b^3 = 3b;

б) 18z^6 / 9z^3 =2z^3;

в) 0,5z • 6z^3z^4 = 3z^8.

3.

a) - 2( 3a - b) + 6a = - 6a + 2b + 6a = 2b;

б) (m - 2n)^2 + 4mn = m^2 - 4mn + 4n^2 + 4mn = m^2 + 4n^2;

в) (x - 6y)( x + 6y) + 9(2y)^2 = x^2 - 36y^2 + 36y^2= x^2.

4.

a) ab - cb = b( a - c);

б) 4a^2 b - 6ab^2 = 2ab( 2a - 3b);

в) 25x^2 - 16y^2 = (5x - 4y)(5x + 4y);

г) 9m^2 - 12mn + 4n^2 = (3m - 2n)^2.