Which of these equations are correct? select three that apply. a. (4.6 × 105) – (2.1 × 104) = 250,000 b. (8.8 × 108) – (6.2 × 107) = 818,000,000 c. (9.9 × 107) – (5.8 × 106) = 9,320,000 d. (7.3 × 106) – (4.2 × 105) = 6,880,000 e. (2.9 × 108) – (1.3 × 107) = 16,000,000 f. (3.6 × 105) – (1.1 × 104) = 349,000