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Simplify each expression. Write any complex numbers in standard form.

 

1) 5-[(-3i+4)-2i]

 

2) -i(-4+2i)(6-7i)+3

 

3) 4-2i/-10+5i * 3-i/-3+i

 

4) 3i+1/2-1/3(1-3i)+2 

 

THANK YOU

 Apr 22, 2016
 #1
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1) 5-[(-3i+4)-2i]

  =5-[-3i+4-2i]

  =5-[-5i+4]

  =5+5i-4

  =1+5i

 

 

2) -i(-4+2i)(6-7i)+3

 =    -i    (-4+2i)(6-7i)    +3

=     -i   [ (-4)(6-7i)   +   2i(6-7i)        ]  +3

=     -i   [ (-24+28i)   +   (12i-14i^2)  ]  +3

=     -i   [ (-24+28i)   +   (12i-14*-1)  ]  +3

=     -i   [ (-24+28i)   +   (12i+14)      ]  +3

=     -i   [     -24+14+28i+12i      ]  +3

=     -i   [     -10+40i    ]                  +3

=        +10i-40i^2             +3

=         +10i-40*-1            +3

=         +10i  +  40           +3

=        +10i  +  43       

=        43   +10i 

 

 

 

I suspect that (3) and maybe (4) need brackets.   ://

 Apr 22, 2016
 #2
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2-

 

Simplify the following:
3+i (2 i-4) (6-7 i)

Factor 2 out of 2 i-4 giving 2 (i-2):
i×2 (i-2) (6-7 i)+3

(i-2) (6-7 i) = -2×6-2 (-7 i)+i×6+i (-7 i) = -12+14 i+6 i+7 = -5+20 i:
i×2 20 i-5+3

Factor 5 out of 20 i-5 giving 5 (4 i-1):
i×2×5 (4 i-1)+3

2×5  =  10:
10 i (4 i-1)+3

i (4 i-1) = -4-i:
10 -i-4+3

Factor -1 from -i-4:
10×-(4+i)+3

-10 (i+4) = -40-10 i:
-10 i-40+3

-40-10 i+3 = -10 i+(3-40) = -37-10 i:
-(10 i)-37

Factor -1 from -(10 i)-37:
Answer: |  -(37+10 i)

 

3-

 

Simplify the following:
4-2 i/(-10)+5 i×3-i/(-3)+i

Multiply numerator and denominator of i/(-10) by -1:
4-2×(-i)/10+5 i×3-i/(-3)+i

(-1)^2 = 1:
4+2 i/10+5 i×3-i/(-3)+i

2/10 = 2/(2×5) = 1/5:
4+i/5+5 i×3-i/(-3)+i

5×3  =  15:
4+i/5+15 i-i/(-3)+i

Multiply numerator and denominator of -i/(-3) by -1:
4+i/5+15 i+i/3+i

Put each term in 4+i/5+15 i+i/3+i over the common denominator 15: 4+i/5+15 i+i/3+i  =  60/15+(3 i)/15+(225 i)/15+(5 i)/15+(15 i)/15:
60/15+(3 i)/15+(225 i)/15+(5 i)/15+(15 i)/15

60/15+(3 i)/15+(225 i)/15+(5 i)/15+(15 i)/15 = (60+3 i+225 i+5 i+15 i)/15:
(60+3 i+225 i+5 i+15 i)/15

Add like terms. 60+3 i+225 i+5 i+15 i  =  60+248 i:
(60+248 i)/15

Factor 4 out of 60+248 i giving 4 (15+62 i):
Answer: |  4 (15+62 i)/15

 

4-

 

Simplify the following:
3 i+1/2-(1-3 i)/(3)+2

Put each term in 3 i+1/2-(1-3 i)/3+2 over the common denominator 6: 3 i+1/2-(1-3 i)/3+2  =  (18 i)/6+3/6-(2-6 i)/6+12/6:
(18 i)/6+3/6+(6 i-2)/6+12/6

Factor 2 out of 6 i-2 giving 2 (3 i-1):
(18 i)/6+3/6+2 (3 i-1)/6+12/6

(18 i)/6+3/6+(2 (3 i-1))/6+12/6 = (18 i+3+(6 i-2)+12)/6:
(18 i+3-2+6 i+12)/6

18 i+3-2+6 i+12 = (3-2+12)+(18 i+6 i) = 13+24 i:
Answer: |  13+24 i/6

 Apr 22, 2016

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