Yes the diagnols of the parallelogram are perpendicular because the angles are perpendicular bisects of each other
75% you find this by dividing 15 by 20 then multiplying the answer by 100
15 / 20 = .75
.75 x 100 = 75
15/20 = 75% of 100
Since you do not want the variable y, you must eliminate 
Therefore, to eliminate it, you must have the opposite of it, making the answer 
{0,-3,-9,5,7}
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Answer: u a c or no
Step-by-step explanation: