Question

Which values of x and y would make the following expression represent a real number?

(4 + 5i)(x + yi)

Answer 1

x = 4, y = 5
x = –4, y = 0
x = 4, y = –5
x = 0, y = 5

Answer 2

i think it has to be the conjugate pair. So then both the i will cancel out and i^2 is -1 so we are left with all real numbers
so 4-5i

Answer 3

so 4 and -5

Answer 4

thankyou I have one more

Answer 5

Which values of p and q would make the value of the following expression equal to 29i?

(2 – 5i)(p + q)i
p = 2, q = 5i
p = –2, q = 5i
p = 2, q = –5i
p = –2, q = –5i

Answer 6

I think its 2 and -5
am I right

Answer 7

have you typed it up correctly?
(2 – 5i)(p + q)i
which makes it
(2 – 5i)(pi + qi)