Which of the following products yield a real number? Select all that apply.

Mathematics

1 answer:

solong [7]2 years ago

4 0

Answer:

The choice 4 and 6 ;

$7i(7i)$

and

$(9 + 3i)(9 - 3i)$

Step-by-step explanation:

$7i(7i) = 49 {i}^{2} = - 49$

__o_o__

$(9 + 3i)(9 - 3i) \\ = 81 - 27i + 27i - 9 {i}^{2} \\ = 81 + 9 \\ = 90$

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Find the quotient of these complex numbers.

stich3 [128]

9514 1404 393

Answer:

C. (45+11i)/29

Step-by-step explanation:

Multiply numerator and denominator by the conjugate of the denominator.

$\dfrac{5-7i}{2-5i}=\dfrac{(5-7i)(2+5i)}{(2-5i)(2+5i)}=\dfrac{(5)(2)+(-7i)(5i) +(5)(5i)+(-7i)(2)}{2^2+5^2}\\\\=\dfrac{(10+35)+(24-14)i}{29}=\boxed{\dfrac{45}{29}+\dfrac{11}{29}i}$

8 0

3 years ago

To begin solving this system of linear equations by elimination,you can add the equations

oksian1 [2.3K]

Answer:

The Correct option is C. Addition Property of Equality.

For above Equation by Elimination we use

Addition Property of equality

Step-by-step explanation:

Given:

Addition Property of Equality :

The property that states that if you add the same number to both sides of an equation, the sides remain equal (i.e., the equation continues to be true.)

Here equation is given as

3x + 4y = 38

+ 5x - 4y = -30

-------------------------------------

8x = 8

------------------------------------

Here +4y and -4y gets cancelled or becomes 0 hence 8x = 8.

For above Equation by Elimination we use

Addition Property of equality

5 0

4 years ago

Evaluate the expression 5a + 5b. Let a = -6 and b = -5.