F.4 數(complex numbers 果D)

If two complex numbers are equal, both of their real part and imaginarypart must be equal.


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1)
a + 2i = 5 - bi

Real part :
a = 5

Imaginary part :
2i = -bi
b = -2


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2)
a - 2i = (4 + i) + (2 + bi)
a - 2i = 4 + i + 2 + bi
a - 2i = 6 + (1 + b)i

Real part :
a = 6

Imaginary part :
-2i = (1 + b)i
1 + b = -2
b = -3

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I hope this can help you~

1)
a+2i=5-bi
a=5
b=2

2)
a-2i=(4+i)+(2+bi)
right=4+2+(b+1)i
right=6+(b+1)i
a=6
b+1=-2
b=-3