1999^2x-6=1

=> 1999^2x-6=1999⁰

=> 2x-6=0

=> 2x=6

=> x=3

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word for each of the blanks.

Can you imagine what life would be like if there were no telephone? You could not call (51)________your friends on the phone and talk to them. If fire (52)________out in your house you could not call the fire department. If somebody was sick, you could not call a doctor.

In our daily life we need to (53)________with one another. We need do this mostly by speaking to other people and listening to (54)________they have to say to us, and when you are close (55)________them you can do this very easily. However, our voices will not travel very far even when we shout.

The man who (56)________this possible was Alexander Graham Bell, a Scotsman, born in Edinburgh in 1847. Bell, a teacher of visible speech who later moved to Canada, (57)________all his spare time experimenting. (58)________enthusiastic was he in his research for a means of sending speech (59)________electricity that he left much time for his day-to-day work and at one time was (60)________ penniless.
Question 51

A.on

B.up

C.for

D.in