Choice A is correct. 7RFDOFXODWH
i ) ơ
i ), add the real parts
RIHDFKFRPSOH[QXPEHUơ ơDQGWKHQDGGWKHLPDJLQDU\
SDUWV
i + 9
i = 12
i 7KHUHVXOWLVơ
i .
Choices B, C, and D are incorrect and likely result from common errors
that arise when adding complex numbers. For example, choice B is
WKHUHVXOWRIDGGLQJ
i DQGơ
i , and choice C is the result of adding 7
and 8.
QUESTION 3
Choice C is correct. The total number of text messages sent by Armand
can be found by multiplying his rate of texting, in number of text
messages sent per hour, by the total number of hours he spent sending
them; that is
P texts/hour × 5 hours = 5
P texts. Similarly, the total number
of text messages sent by Tyrone is his hourly rate of texting multiplied
by the 4 hours he spent texting:
S texts/hour × 4 hours = 4
S texts. The
total number of text messages sent by Armand and Tyrone is the sum of
the total number of messages sent by Armand and the total number of
messages sent by Tyrone: 5
P + 4
S .
Choice A is incorrect and arises from adding the coefficients and
multiplying the variables of 5
P and 4
S . Choice B is incorrect and is
the result of multiplying 5
P and 4
S . The total number of messages
sent by Armand and Tyrone should be the sum of 5
P and 4
S , not the
product of these terms. Choice D is incorrect because it multiplies
Armand’s number of hours spent texting by Tyrone’s hourly rate of
$16:(5(;3/$1$7,216
̝_̝
6$73UDFWLFH7HVW texting, and vice versa. This mix-up results in an expression that
does not equal the total number of messages sent by Armand and
Tyrone.
48(67,21
