Which of the following is a conjugate for 7 + iSquare root of 2?

1. - 7 + iSquare root of 2

2. 7 - iSquare root of 2

3. iSquare root of 2 + 7

4. iSquare root of 2 - 7

Our complex number is:

7+i√2

Conjugate complex number is a number that has opposite sign of its imaginary part than its original. In this case imaginary part is + i√2

Conjugate value of + i√2 is - i√2 (just change the sign to opposite one)

Answer is:

7 - i√2

Conjugate of a complex number a + ib = a - ib.

Therefore, conjugate of 7 + isqrt (2) = 7 - isqrt (2)