I don’t understand this can someone help me!!

Determine whether the quadrilateral below is a parallelogram. justify/explain your answer (this means back it up! give specific information that supports your decision. writing just "yes" or "no" will result in no credit.)

The frequency table shows a set of data collected by a doctor for adult patients who were diagnosed with a strain of influenza. patients with influenza age range number of sick patients 25 to 29 30 to 34 35 to 39 40 to 45 which dot plot could represent the same data as the frequency table? patients with flu

X+ y = 5 ; x - y =3 solve using linear combination