Q. Express as a complex number in simplest a+bi form:1+3i14−28iAnswer:
Multiply by Conjugate: To express the complex fraction(14−28i)/(1+3i) in the form a+bi, we need to eliminate the imaginary part from the denominator. We do this by multiplying the numerator and the denominator by the complex conjugate of the denominator.The complex conjugate of (1+3i) is (1−3i).So, we multiply both the numerator and the denominator by (1−3i).
Perform Multiplication: Now, we perform the multiplication:(14−28i)×(1−3i)/(1+3i)×(1−3i)We distribute the terms in the numerator and the denominator.
Calculate Numerator: First, we calculate the numerator:(14−28i)×(1−3i)=14(1)−14(3i)−28i(1)+28i(3i)=14−42i−28i+84i2Since i2=−1, we replace i2 with −1:=14−42i−28i−84=14−84−70i=−70−70i
Calculate Denominator: Next, we calculate the denominator:(1+3i)×(1−3i)=1(1)−1(3i)+3i(1)−3i(3i)=1−3i+3i−9i2Again, since i2=−1, we replace i2 with −1:=1−9(−1)=1+9=10
Divide by Denominator: Now we have the numerator and the denominator:Numerator: −70−70iDenominator: 10We divide both parts of the numerator by the denominator:(−70−70i)/10= −70/10−(70i/10)= −7−7i
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