Найдите значения выражения:(-5/8)*(-4/5)*(-3/4)*(-2/3)*(-1/2);(-7/12)*(-6/7)*(-5/6)*(-4/5)+2/3;(-11/15)*(-10/11)*(-9/10)+(-7/9)*(-6/7)+4/15

а) (-5/8) * (-4/5) * (-3/4) * (-2/3) * (-1/2) = -1/8 = -0,125; 

1. (-5/8) * (-4/5) = -5 *(-4)/8 * 5 = -1 * (-1)/2 * 1 = 1/2;

2. 1/2 * (-3/4) = 1 * (-3)/2 * 4 = -3/8;

3. -3/8 * (-2/3) = -3 * (-2)/8 * 3 = -1 * -1/4 * 1 = 1/4;

4. 1/4 * (-1/2) = 1 * (-1)/4 * 2 = -1/8 = -0,125;  

б) (-7/12) * (-6/7) * (-5/6) * (-4/5) + 2/3 = 1; 

1. -7/12 * (-6/7) = 42/84 = 1/2;

2. 1/2 * (-5/6) = -5/12;

3. -5/12 *(-4/5) = 20/60 = 1/3;

4. 1/3 + 2/3 = (1 + 2)/3 = 3/3 = 1; 

в) (-11/15) * (-10/11) * (-9/10) + (-7/9) * (-6/7) + 4/15 = 1/3; 

1. -11/15 * (-10/11) = 110/165 = 2/3;

2. 2/3 * (-9/10) = -18/30 = -3/5;

3. -7/9 * (-6/7) = 42/63 = 2/3;

4. -3/5 + 2/3 = -9/15 + 10/15 = (-9 + 10)/15 = 1/15;

5. 1/15 + 4/15 = 5/15 = 1/3;