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Sat 2015 Practice Test #1 Answer Explanationssat-practice-test-1-answersChoice B is correct.
The minimum value of the function corresponds
to the
y
-coordinate of the point on the graph that has the smallest
y
-coordinate on the graph. Since the smallest
y
-coordinate belongs to
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Iơ ơ7KHUHIRUHWKHPLQLPXPYDOXHRII
(
[
) is at
[ ơ
&KRLFH$LVLQFRUUHFWơLVWKHOHDVWYDOXHIRUDQ[
-coordinate, not the
y
-coordinate, of a point on the graph of
y
=
I
(
[
). Choice C is incorrect;
it is the minimum value of
I
, not the value of
[
that corresponds to the
minimum of
I
. Choice D is incorrect; it is the value of
[
for which the
value of
I
(
[
) has its maximum, not minimum.
QUESTION 18
Choice A is correct.
6LQFHLVDVROXWLRQWRWKHV\VWHPRI
LQHTXDOLWLHVVXEVWLWXWLQJIRU[DQGIRU
y
in the given system must
result in two true inequalities. After this substitution,
y
ơ[
+
D
EHFRPHVD
, and
y
>
[
+
EEHFRPHV!E
. Hence,
D
is positive and
E
is negative. Therefore,
D
>
E
.
Choice B is incorrect because
E
>
D
cannot be true if
E
is negative
and
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DQH[DPSOHZKHUHLVDVROXWLRQWRWKHV\VWHPEXW_D__E
|;
for example, if
D
= 6 and
E ơ&KRLFH'LVLQFRUUHFWEHFDXVHWKH
equation
D ơEGRHVQŞWKDYHWREHWUXHIRUH[DPSOHLVDVROXWLRQ
to the system of inequalities if
D
= 1 and
E ơ
QUESTION 19
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