If (x + yi) / i = ( 7 + 9i ) , where x and y are real, what is the value of (x + yi)(x - yi)?	Choose the correct option:	A) 110	B) 120	C) 130	D) 140	E) 150
(x + yi) / i = ( 7 + 9i )   (x + yi) = i(7 + 9i) = -9 + 7i   (x + yi)(x - yi) = (-9 + 7i)(-9 - 7i) = 81 + 49= 
<gadget id="calculator">81 + 49</gadget>
<output>130</output>
130   130ORRE130T ANSWER IS 1300130
<result>C</result>
If (x + yi) / i = ( 7 + 9i ) , where x and y are real, what is the value of (x + yi)(x - yi)?