Question

Which of the following is a conjugate for −10 + 3i?

Answer 1

http://www.mathsisfun.com/numbers/images/complex-conjugate.gif

Answer 2

The conjugate of a + bi is a - bi.

Answer 3

so the answer would be 3i − 10?

Answer 4

No.
Notice what I wrote above.
To get the complex conjugate of a + bi, a + bi becomes a - bi.
a is the real part. It was a and it remains a. There is no change with the real part.
The imaginary part was +bi and becomes -bi. The imaginary part changes sign.
Try again. Keep the order the same, the real part followed by the imaginary part.

Answer 5

im completely lost :/ @mathstudent55

Answer 6

Ok, here are a few examples. Sometimes it's easier to learn something by looking at examples than looking at the rule.

Example 1.
The conjugate of 2 + 4i is 2 - 4i
(Notice the real part, 2, remained the same. The imaginary part, +4i changed to -4i).

Example 2.
The conjugate of -5 - 5i is -5 + 5i
(Notice the real part, -5, remained the same. The imaginary part, -5i changed to +5i).

Example 3.
The conjugate of -4 + 8i is -4 - 8i
(Notice the real part, -4, remained the same. The imaginary part, +8i changed to -8i).

Example 4.
The conjugate of 6 - 7i is 6 + 7i
(Notice the real part, 6, remained the same. The imaginary part, -7i changed to +7i).

In every example above, the real part (number without i) remained the same. The imaginary part (number with i) changed sign. This is how you find the complex conjugate of a complex number.

Answer 7

got it thankyou ! (:

Answer 8

The answer is -10 - 3i

Answer 9

wlcm

Answer 10

wouldnt it just be 10-3i?

Answer 11

No.
10 - 3i is the additive inverse of -10 + 3i.
Here we were not asked for the additive inverse.
We were asked for the complex conjugate.

To find the complex conjugate of a complex number, do what is written above.
Keep the real part the same and change the sign of the imaginary part.

-10 + 3i has a real part of -10 and an imaginary part of 3i.
To get the complex conjugate, keep the real part the same. -10 remains as -10.
The imaginary part changes sign. 3i becomes -3i.
The answer is -10 - 3i

Answer 12

@cosmicchild did you not read anything he wrote? I didn't get this then I saw that and got it in about 5 seconds.....