1)a=-1;b=4; 2)a=-4;b=2; 3)a=1,5;b=6; 4)a=-2,3;b=5;5)a=-7;b=-5 6)a=-4;b=5

Выполним действия с известными значениями а и b:

1) a = -1; b = 4; 

a + b = -1 + 4 = 4 - 1  = 3;

a - b = -1 - 4 = - 5;

b - a = 4 - (-1) = 4 + 1 = 5;

2) a = -4; b = 2; 

a + b = -4 + 2 = -2;

a - b = -4 - 2 = -6; 

b - a = -2 - (-4) = -2 + 4 = 4 - 2 = 2;

3) a =1,5; b = 6; 

a + b = 1.5 + 6 = 7.5;

a - b = 1.5 - 6 = - 4.5;

b - a = 6 - 1.5 = 4.5;

4) a = -2,3; b=5;

a + b = -2.3 + 5 = 5 - 2.3 = 2.7;

a - b = -2.3 - 5 = - 7.3;

b - a = 5 + 2.3 = 7.3;

5) a = -7; b = -5; 

a + b = -7 -5 = 12; 

a - b = -7 + 5 = -2; 

b - a = -5 + 7 = 2; 

6) a = -4; b = 5; 

a + b = -4 + 5 = 1; 

a - b = -4 - 5 = -9; 

b - a = 5 + 4 = 9.