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问题 填空题

方程x2-3x-10=0的两根之比为______．

答案

∵x2-3x-10=0

∴（x-5）（x+2）=0

∴x1=5，x2=-2

∴方程x2-3x-10=0的两根之比为-

5
2
或-
2
5
．

单项选择题

Mr. Faugel was convinced that student nervousness had affected their scores; to reduce the anxiety of these students who had already been tested, he gave 22 of them a beta blocker before readministration of the test. Their scores improved significantly. The other 8 students (who did not receive the beta blockers) improved only slightly. Second-time test-takers nationwide had average improvements which were similar to those in Faugel’’s non-beta blocker group. Beta blockers are prescription drugs which have been around for 25 years. These medications, which interfere with the effects of adrenalin, have been used for heart conditions and for minor stress such as stage fright. Now they are used for test anxiety. These drugs seem to help test-takers who have low scores because of test fright, but not those who do not know the material. Since there can be side effects from these beta blockers, physicians are not ready to prescribe them routinely for all test-takers.

Where is the only place a person can obtain beta blockers

A．Supermarket.

B．Convenience store.

C．Stationary store.

D．Doctor’s office.
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单项选择题

某施工过程在不影响工程计划总工期的前提下，该施工过程最迟必须在第几天开始施工的时间称为（）

A、最早可能开始时间ES

B、自由时差FF

C、最迟必须开始时间LS

D、最早完成时间EF
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