Q. Express as a complex number in simplest a+bi form:2−7i22−24iAnswer:
Multiply by Conjugate: To express the complex fraction(22−24i)/(2−7i) 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 (2−7i) is (2+7i).Now, multiply the numerator and the denominator by (2+7i).
Numerator Multiplication: Perform the multiplication in the numerator: (22−24i)×(2+7i). This involves using the distributive property (FOIL method) to expand the product. (22×2)+(22×7i)+(−24i×2)+(−24i×7i) = 44+154i−48i−168i2 Since i2=−1, replace −168i2 with 168. = 44+106i+168 = 212+106i
Denominator Multiplication: Perform the multiplication in the denominator: (2−7i)×(2+7i). This is a difference of squares, which simplifies to: (22)−(7i)2=4−49i2 Since i2=−1, replace −49i2 with 49. =4+49=53
Divide and Simplify: Now, divide the simplified numerator by the simplified denominator to get the complex number in a+bi form.(212+106i)/53Divide both the real part and the imaginary part by 53.53212+(53106)i= 4+2i
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