Also, note that when you simplify an
inequality
, the steps of multiplying or dividing both
sides by a negative number change the direction of
the inequality; for example,
if
then
So the relationship in the final, simplified inequality may be
the
opposite
of the relationship between Quantities A and B. This is another reason to
consider the impact of each step carefully.
7.
Quantity A
Quantity B
A. Quantity A is greater.
B. Quantity B is greater.
C. The two quantities are equal.
D. The relationship cannot be determined from the information given.
Explanation
Set up the initial comparison:
Then simplify:
Step 1: Multiply both sides by 2 to get
Step 2: Add
to
both sides to get
Step 3: Simplify the right-hand side using the fact that
to get
The resulting relationship is
equal to
(=). In reverse order, each simplification step
implies
equal to
in the preceding comparison. So Quantities A and B are also equal.
Thus
the correct answer is Choice C
,
the two quantities are equal
.
8.
Quantity A
Quantity B
A. Quantity A is greater.
B. Quantity B is greater.
C. The two quantities are equal.
D. The relationship cannot be determined from the information given.
19
Explanation
Set up the initial comparison:
Then simplify by noting that the quadratic polynomial
can be factored:
Step 1: Subtract 2
x
from both sides to get
Step 2: Factor
the left-hand side to get
The left-hand side of the comparison is the square of a number. Since the square of a
number is always greater than or equal to 0, and 0 is greater than
the simplified
comparison
is the inequality
and the resulting relationship is
greater than
(>). In
reverse order, each simplification step implies the inequality
greater than
(>) in the
preceding comparison. Therefore, Quantity A is greater than Quantity B.
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