# NCERT Class 11-Math's: Chapter –5 Complex Numbers and Quadratic Equations Part 10

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**Question 16:**

are two complex numbers such that and then show that .

**Answer:**

Let

Given that

And

Now,

Hence proved.

**Question 17:**

If then show that the real part of is zero.

**Answer:**

Let

Now,

Since

Hence, the real part of is zero.

**Question 18:**

If are two pairs of conjugate complex numbers, then find

.

**Answer:**

Given and are conjugate complex numbers.

is,

He negative side of the real axis

Similarly,

**Question 19:**

If , then

Show that

**Answer:**

Given

Now,

Hence Proved.