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[7 - 3i] To find the conjugate: the sign of the real part stays the same, and the sign of the imaginary part is reversed. So the conjugate of [7 + 3i] is [7 - 3i]

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-3 + 8i

Q: What is complex conjugate for the number 7 3i?

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The conjugate is 7 - 3i is 7 + 3i.

The conjugate is 7-5i

Yes, all real numbers are complex numbers.

They are 7 ± 11i

Better get a textbook that explains this in more detail. You can also get a brief summary at Wikipedia, or other online sites. In any case, here is a brief summary. For addition and substraction, you add (or subtract) the real and imaginary parts separately. For example, (4 + 3i) + (7 - 2i) = 11 + 1. For multiplication, multiply each part of one number with each part of the other number - and remember that i2 = -1. For example, (4 + 3i) x (7 - 2i) = 28 - 8i + 21i - 6i2 = 28 + 13i - 6(-1) = 34 + 13i. Division is a bit more complicated. For example, to divide by (3 + 4i) you have to multiply numerator and denominator by the complex conjugate of this number, that is, change the sign of the imaginary part; in this case, (3 - 4i). Multiplication and division are actually quite a lot easier if you convert the complex number to polar coordinates, that is, a distance and an angle. Here is a quick example: (4 angle 30 degrees) x (5 angle 20 degrees) = (4 x 5) angle (30 + 20 degrees) = 20 angle 50 degrees (a length of 20, at an angle of 50 degrees). Most scientific calculators have special functions to convert from rectangular to polar coordinates and back.

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The conjugate is 7 - 3i is 7 + 3i.

[7 - 3i] To find the conjugate: the sign of the real part stays the same, and the sign of the imaginary part is reversed. So the conjugate of [7 + 3i] is [7 - 3i]

The conjugate is 7-5i

To get the conjugate simply reverse the sign of the complex part. Thus conj of 7-4i is 7+4i

Yes, easily. Even though the question did not ask what the polynomial was, only if I could find it, here is how you would find the polynomial: Since the coefficients are rational, the complex (or imaginary) roots must form a conjugate pair. That is to say, the two complex roots are + 3i and -3i. The third root is 7. So the polynomial, in factorised form, is (x - 3i)(x + 3i)(x - 7) = (x2 + 9)(x - 7) = x3 - 7x2 + 9x - 63

Yes. Consider, if you can factor complex numbers, then logically, you should be able to take two complex numbers, multiply them together, and get a third. That can indeed be done. For example: (4i + 7)(3i + 2) = -12 + 8i + 21i + 14 = 29i + 2 Therefore, the complex number 29i + 2 must be divisible by 4i + 7 and 3i + 2.

7

The conjugate of a complex number can be found by multiplying the imaginary part by -1, then adding the "real" part back. (-2i) * -1 = 2i, so the conjugation is 7+2i

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the conjugate 7-2i

7

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