Q. Express as a complex number in simplest a+bi form:−9−7i8+3iAnswer:
Multiply by Conjugate: To divide complex numbers, we multiply the numerator and denominator by the conjugate of the denominator. The conjugate of a complex number a+bi is a−bi. So, the conjugate of −9−7i is −9+7i.
Multiply Numerator and Denominator: Now, we multiply both the numerator and the denominator by the conjugate of the denominator: egin{equation}(8 + 3i) * (−9 + 7i) / ((−9 - 7i) * (−9 + 7i))egin{equation}
Expand Numerator: First, we'll multiply out the numerators using the distributive property (FOIL method): (8×−9)+(8×7i)+(3i×−9)+(3i×7i)
Calculate Numerator: Now, we calculate each term:−72−56i−27i+21i2Remembering that i2=−1, we substitute −1 for i2:−72−56i−27i−21
Combine Like Terms: Combine like terms in the numerator:−72−21−56i−27i−93−83i
Expand Denominators: Now, we'll multiply out the denominators:(−9×−9)+(−9×7i)+(−7i×−9)+(−7i×7i)
Calculate Denominator: Calculate each term in the denominator:81−63i+63i−49i2Again, substituting −1 for i2:81−49(−1)
Simplify Denominator: Simplify the denominator: 81+49=130
Simplified Fraction: Now we have the simplified numerator and denominator: 130−93−83i
Divide Real and Imaginary Parts: Divide both the real part and the imaginary part of the numerator by the denominator:−13093−13083i
Final Answer: Simplify both fractions to get the final answer in a+bi form:−13093−13083i
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