Q. If (3−2i)(3−i)(2+i)=a+ib, where a and b are real numbers and the imaginary number i is such that i2=−1, what is the value of (2a+3b)?
Multiply Complex Numbers: Step 1: Multiply the first two complex numbers (3−2i) and (3−i).Calculation: (3−2i)(3−i)=3(3)+3(−i)−2i(3)−2i(−i)=9−3i−6i+2i2=9−9i+2(−1)=7−9i.
Multiply by Third Number: Step 2: Multiply the result by the third complex number (2+i).Calculation: (7−9i)(2+i)=7(2)+7(i)−9i(2)−9i(i)=14+7i−18i−9i2=14−11i−9(−1)=23−11i.
Identify Real and Imaginary Parts: Step 3: Identify the real part a and the imaginary part b from the result.Calculation: From 23−11i, a=23 and b=−11.
Calculate Value: Step 4: Calculate the value of (2a+3b).Calculation: 2a+3b=2(23)+3(−11)=46−33=13.
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