Question

Which values of x and y would make the following expression represent a real number?
(4 + 5i)(x + yi)

A. x = 4, y = 5
B. x = –4, y = 0
C. x = 4, y = –5
D. x = 0, y = 5

Answer 1

\[(a+bi)(a-bi)=a^2+b^2\] a real number

Answer 2

HI!!

Answer 3

if that is not clear, you are being asked for the conjugate of \(4+5i\) which is \(4-5i\)

Answer 4

or just pick C because it is always C every time

Answer 5

Thank you @misty1212

Answer 6

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