（1）

　　（2） x = 90

　　Recall that a triangle is a right triangle if and only if the square of the

　　longest side is equal to the sum of the squares of the shorter sides （Pythag

　　orean Theorem）。 Hence， （1） implies that the triangle is a right triangle. So

　　the area of the triangle is （6）（8）/2. Note， there is no need to calculate t

　　he area——we just need to know that the area can be calculated. Hence， the an

　　swer is either A or D.

　　Turning to （2）， we see immediately that we have a right triangle. Hence， aga

　　in the area can be calculated. The answer is D.

　　Example 3： Is p < q ？

　　（1） p/3 < q/3

　　（2） -p + x > -q + x

　　Multiplying both sides of p/3 < q/3 by 3 yields p < q.

　　Hence， （1） is sufficient. As to （2）， subtract x from both sides of -p + x >

　　-q + x， which yields -p > -q.

　　Multiplying both sides of this inequality by -1， and recalling that multiply

　　ing both sides of an inequality by a negative number reverses the inequality

　　， yields p < q.

　　Hence， （2） is also sufficient. The answer is D.

　　Example 4： If x is both the cube of an integer and between 2 and 200， what i

　　s the value of x？

　　（1） x is odd.

　　（2） x is the square of an integer.

　　Since x is both a cube and between 2 and 200， we are looking at the integers

　　：

　　which reduce to

　　8， 27， 64， 125

　　Since there are two odd integers in this set， （1） is not sufficient to uniqu

　　ely determine the value of x. This eliminates choices A and D.

　　Next， there is only one perfect square， 64， in the set. Hence， （2） is suffic

　　ient to determine the value of x. The answer is B.

　　Example 5： Is CAB a code word in language Q？