Tìm phân thức Q thỏa mãn điều kiện: 2 a − 6 a 3 − 3 a 2 − a + 3 + Q = 6 a − 3 − 2 a 2 1 − a 2 , với a ≠ ± 1  và  a ≠ 3 .

Thực hiện các phép tính sau:

a) ab a 2 − b 2 − a 2 b 2 − a 2  với a ≠ ± b ;  

b) 1 u − 6 u 2 − 36 u − 18 36 u 2 − 1  với u ≠ 0  và u ≠ ± 1 6 .

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 25 to 29.

        It is true that digital manufacturing does cut out the middle-man. More and more routine, repetitive assembly tasks will be taken (25)______ by machines. But as certain jobs disappear, new ones open up in other parts of the factory. Germany in many ways exemplifies this trend. Today, German manufacturers (26)______ three times more robots than U.S. companies, but they also still employ more humans. Relative to the size of our economies, German's manufacturing workforce is twice the size of America's.

        From its very beginning, the fourth Industrial revolution has never presented manufacturers with an

either-or choice - robots or humans. It has always been about combining the talents of (27)______ . (28) ______, it is the convergence of artificial and human intelligence that will enable manufacturers to achieve a new era of speed, flexibility, efficiency and connectivity in the 21st century. Machines have the ability to assemble things faster than any human ever could, but humans possess the analytics, domain expertise and valuable knowledge (29)______ to solve problems and optimize factory floor production.

(Adapted from: http://time.com/4940374/joe-kaeser-siemens-robots-jobs/)

Điền vào ô 28.

A. Alternatively

B. Ultimately

C. Correspondingly

D. Consequently