Question 173132
8)


(3 + 2i) + (4 + xi) = 7 - 5i



(3 + 4) + (2i + xi) = 7 - 5i



-----> 3+4 = 7 and 2i+xi=5i


2i+xi=-5i


xi=-7i


x=-7 <----answer




9)


Which of the following is not sufficient to prove that a quadrilateral is a parallelogram?



The answer is (4) consecutive angles are supplementary 



Example:


Draw a trapezoid with the top and bottom parallel. Now make one side completely vertical. This will make 2 consecutive angles that add to 180, but it won't be a parallelogram