Q. Express as a complex number in simplest a+bi form:−3−2i9−7iAnswer:
Multiply Conjugate: To simplify the expression (9−7i)/(−3−2i), we need to eliminate the complex number in the denominator. We do this by multiplying the numerator and the denominator by the conjugate of the denominator. The conjugate of (−3−2i) is (−3+2i).
Expand Numerator: Multiply the numerator and the denominator by the conjugate of the denominator: [(9−7i)(−3+2i)]/[(−3−2i)(−3+2i)].
Expand Denominator: First, we'll expand the numerator using the distributive property (FOIL method): (9×−3)+(9×2i)+(−7i×−3)+(−7i×2i)=−27+18i+21i−14i2.Since i2=−1, we can replace −14i2 with 14.So, the expanded numerator is −27+18i+21i+14.
Simplify Numerator: Now, we'll expand the denominator: (−3×−3)+(−3×2i)+(−2i×−3)+(−2i×2i)=9−6i+6i−4i2. Again, since i2=−1, we can replace −4i2 with 4. So, the expanded denominator is 9+4.
Simplify Denominator: Simplify the expanded numerator and denominator:Numerator: −27+18i+21i+14=−13+39i.Denominator: 9+4=13.
Divide Numerator: Now, divide the simplified numerator by the simplified denominator: (−13+39i)/13.
Divide Real and Imaginary: Divide both the real part and the imaginary part of the numerator by the denominator: (−1313)+(1339i).
Final Simplification: Simplify both parts:−1+3i.This is the expression in a+bi form.
More problems from Simplify variable expressions using properties