Q. Divide the following complex numbers.−3+5i10+40i
Write Problem: Write down the problem to solve.We need to divide the complex number (10+40i) by the complex number (−3+5i).
Multiply by Conjugate: Multiply the numerator and the denominator by the conjugate of the denominator. The conjugate of (−3+5i) is (−3−5i). We multiply both the numerator and the denominator by this conjugate to remove the imaginary part from the denominator. (−3+5i)⋅(−3−5i)(10+40i)⋅(−3−5i)
Apply FOIL to Numerators: Apply the distributive property (FOIL) to multiply out the numerators.(10+40i)×(−3−5i)=10×(−3)+10×(−5i)+40i×(−3)+40i×(−5i)=−30−50i−120i−200i2Since i2=−1, we replace −200i2 with 200.=−30−50i−120i+200=170−170i
Apply FOIL to Denominators: Apply the distributive property (FOIL) to multiply out the denominators.(−3+5i)∗(−3−5i)=(−3)∗(−3)+(−3)∗(−5i)+5i∗(−3)+5i∗(−5i)=9+15i−15i−25i2Since i2=−1, we replace −25i2 with 25.=9+15i−15i+25=9+25=34
Divide Simplified Numbers: Divide the simplified numerator by the simplified denominator.(170−170i)/34= (170/34)−(170i/34)= 5−5i
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