Respuesta :
Answer:
Step-by-step explanation:
Given the following complex numbers, we are to expressed them in the form of a+bi where a is the real part and b is the imaginary part of the complex number.
1) (2-6i)+(4+2i)
open the parenthesis
= 2-6i+4+2i
collect like terms
= 2+4-6i+2i
= 6-4i
2) (6+5i)(9-2i)
= 6(9)-6(2i)+9(5i)-5i(2i)
= 54-12i+45i-10i²
= 54+33i-10i²
In complex number i² = -1
= 54+33i-10(-1)
= 54+33i+10
= 54+10+33i
= 64+33i
3) For the complex number 2/(3-9i), we will rationalize by multiplying by the conjugate of the denominator i.e 3+9i
= 2/3-9i*3+9i/3+9i
=2(3+9i)/(3-9i)(3+9i)
= 6+18i/9-27i+27i-81i²
= 6+18i/9-81(-1)
= 6+18i/9+81
= 6+18i/90
= 6/90 + 18i/90
= 1/15+1/5 i
4) For (3 − 5i)(7 − 2i)
open the parenthesis
= 3(7)-3(2i)-7(5i)-5i(-2i)
= 21-6i-35i+10i²
= 21-6i-35i+10(-1)
= 21-41i-10
= 11-41i
Simplified form of the given expressions will be,
1). 6 - 4i
2). 64 + 33i
3). [tex]\frac{1}{15}+\frac{1}{5}i[/tex]
4). [tex]\frac{31}{53}-\frac{31}{53}i[/tex]
1). In a complex number (a + bi),
a = Real part of the complex number
bi = Imaginary part
Expression given in the question → (2 - 6i) + (4 + 2i)
Rule to solve the given expression,
"Add real part and imaginary part of two complex numbers separately"
(2 - 6i) + (4 + 2i) = (2 + 4) + (-6i + 2i)
= 6 + (-4i)
= 6 - 4i
Therefore, simplified form of the given expression will be (6 - 4i).
2). Given expression → (6 + 5i)(9 - 2i)
Rule to solve the expression → i² = -1
(6 + 5i)(9 - 2i) = 6(9 - 2i) + 5i(9 - 2i)
= 54 - 12i + 45i - 10i²
= 54 - 12i + 45i + 10 [Since, i² = -1]
= (54 + 10) + (45i - 12i)
= 64 + 33i
Therefore, simplified form of the given expression will be (64 + 33i).
3). Given expression → [tex]\frac{2}{3-9i}[/tex]
Multiply numerator and denominator with the conjugate of (3 - 9i) to convert the expression into (a + bi).
[tex]\frac{2}{3-9i}= \frac{2(3+9i)}{(3-9i)(3+9i)}[/tex]
[tex]=\frac{2(3+9i)}{3^2-(9i)^2}[/tex]
[tex]=\frac{6+18i}{9-81(-1)}[/tex]
[tex]=\frac{6+18i}{9+81}[/tex]
[tex]=\frac{6+18i}{90}[/tex]
[tex]=\frac{6(1+3i)}{90}[/tex]
[tex]=\frac{1}{15}+\frac{1}{5}i[/tex]
Therefore, simplified form of the given expression will be [tex]\frac{1}{15}+\frac{1}{5}i[/tex]
4). Given expression → [tex]\frac{(3-5i)}{(7-2i)}[/tex]
Multiply numerator and denominator with the conjugate of the denominator.
[tex]\frac{(3-5i)}{(7-2i)}=\frac{(3-5i)(7+2i)}{(7-2i)(7+2i)}[/tex]
[tex]=\frac{3(7+2i)-5i(7+2i)}{7^2-(2i)^2}[/tex]
[tex]=\frac{21+4i-35i-10i^2}{49-4(-1)}[/tex]
[tex]=\frac{21-31i+10}{53}[/tex]
[tex]=\frac{31-31i}{53}[/tex]
[tex]=\frac{31}{53}-\frac{31}{53}i[/tex]
Therefore, simplified form of the given expression will be [tex]\frac{31}{53}-\frac{31}{53}i[/tex].
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