Q. Express as a complex number in simplest a+bi form:−5+2i−9−6iAnswer:
Multiply by Conjugate: To simplify the complex fraction(−9−6i)/(−5+2i), we need to eliminate the imaginary part from the denominator. We do this by multiplying both the numerator and the denominator by the conjugate of the denominator. The conjugate of (−5+2i) is (−5−2i).
Expand Numerator: Now, we multiply the numerator and the denominator by the conjugate of the denominator: ((−9−6i)×(−5−2i))/((−5+2i)×(−5−2i)).
Calculate Numerator: First, we'll expand the numerator:(−9−6i)∗(−5−2i)=(−9∗−5)+(−9∗−2i)+(−6i∗−5)+(−6i∗−2i).
Combine Like Terms: Now, we calculate the products in the numerator:45+18i+30i+12i2.Since i2=−1, we replace 12i2 with −12:45+18i+30i−12.
Expand Denominator: Combine like terms in the numerator: (45−12)+(18i+30i)=33+48i.
Calculate Denominator: Next, we'll expand the denominator: (−5+2i)∗(−5−2i)=(−5∗−5)+(−5∗−2i)+(2i∗−5)+(2i∗−2i).
Combine Like Terms: Now, we calculate the products in the denominator: 25−10i−10i+4i2. Again, since i2=−1, we replace 4i2 with −4: 25−10i−10i−4.
Simplify Numerator and Denominator: Combine like terms in the denominator: \(25 - 4) - (10i - 10i) = 21\
Divide Numerator by Denominator: Now we have the simplified numerator and denominator:Numerator: 33+48iDenominator: 21We divide both parts of the numerator by the denominator to get the complex number in a+bi form:(2133)+(2148i).
Simplify Complex Number: Simplify both parts of the complex number: 2133 simplifies to 711 and 2148 simplifies to 716. So, the complex number in a+bi form is: (711)+(716)i.
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