What is the value of the expression given below?
(5 + 3i) - (5 + 3i)(5 – 5i)
A. –5 + 371
B. 35 – 131
OC -5 – 371
D. –35 + 131

Respuesta :

D -35+131

this is your answer

Answer:

D. -35+13i

Step-by-step explanation:

We have the expression [tex](5+3i)-(5+3i)(5-5i)[/tex], first we have to solve:

[tex](5+3i)(5-5i)[/tex] we have to apply distributive property.

Distributive property: [tex](a+b)(c+d)=ac+ad+bc+bd[/tex]

Then,

[tex](5+3i)(5-5i)=5.(5)+5.(-5i)+3i.(5)+3i.(-5i)\\(5+3i)(5-5i)=25-25i+15i-15i^2\\(5+3i)(5-5i)=25-10i+15\\(5+3i)(5-5i)=(40-10i)[/tex]

Observation: [tex]i^2=(-1)[/tex] then [tex]-15i^2=-15.(-1)=15[/tex]

Now replacing [tex](5+3i)(5-5i)=(40-10i)[/tex] in [tex](5+3i)-(5+3i)(5-5i)[/tex]:

[tex](5+3i)-(40-10i)=5+3i-40+10i=(5-40)+(3i+10i)=-35+13i[/tex]

Then the correct answer ir: D. -35+13i