Adding and subtracting complex numbers Quiz 1

Question 1

Subtract $$7 - 3i $$ from $$5 + 6i $$

Accepted Answer

$$ - 2 + 9i $$

Answer

$$ - 2 - 9i $$

Answer

$$9 - 2i $$

Answer

$$2 + 9i $$

Question 2

Solve $$\left( {3 - \sqrt { - 25} } \right) - \left( { - 2 + \sqrt { - 49} } \right)$$

Accepted Answer

$$5 - 12i $$

Answer

$$12 - 5i $$

Answer

$$5 - \sqrt { - 74} $$

Answer

$$1 - \sqrt { - 74} $$

Question 3

Find the value of $$x$$ and $$y$$ if $$\left( {x + i y} \right) + \left( {2 + i } \right) = 3 - i $$ where $$x$$ and $$y$$ are real.

Accepted Answer

$$1, - 2$$

Answer

$$ - 2,5$$

Answer

$$5, - 2$$

Answer

$$2,1$$

Question 4

Simplify $$\left( {2 + 5i } \right)\left( {3 - 4i } \right)$$

Accepted Answer

$$26 + 7i $$

Answer

$$26 - 7i $$

Answer

$$26 + 3i $$

Answer

$$ - 14 - 7i $$

Question 5

Add $$\dfrac{{2 + i \sqrt 7 }}{{2 + 3i }}$$ and $$\dfrac{{3 + i \sqrt 7 }}{{3 + 2i }}$$.

Accepted Answer

$$\dfrac{{\left( {12 - 5\sqrt 7 } \right) + i\left( {13 + 5\sqrt 7 } \right)}}{{13t}}$$

Answer

$$\dfrac{{\left( {12 - 5\sqrt 7 } \right) + i\left( {13 + 5\sqrt 7 } \right)}}{{13}}$$

Answer

$$\dfrac{{\left( {12 - 5\sqrt 7 } \right) - i \left( {13 + 5\sqrt 7 } \right)}}{{13}}$$

Answer

None of these