Упрости выражения и найди их значения:

а) 5(a - 1) - (2a + 3) = 5a - 5 - 2a - 3 = 3a - 8. При a = -2/3, 3(-2/3) - 8 = -2 - 8 = -10.

б) -2(1 - 3b) + 4(2 - b) = -2 + 6b + 8 - 4b = 2b + 6. При b = -0.2, 2(-0.2) + 6 = -0.4 + 6 = 5.6.

в) -(x + 1 9/14) + 2x = -x - 1 9/14 + 2x = x - 1 9/14. При x = -1.5, -1.5 - 1 9/14 = -1 7/14 - 1 9/14 = -2 16/14 = -3 8/14 = -3 4/7.

г) 1 1/3 + 2y - (2 3/4 - y) = 1 1/3 + 2y - 2 3/4 + y = 3y + 1 1/3 - 2 3/4 = 3y + 4/3 - 11/4 = 3y + 16/12 - 33/12 = 3y - 17/12. При y = -1/9, 3(-1/9) - 17/12 = -1/3 - 17/12 = -4/12 - 17/12 = -21/12 = -7/4 = -1.75.