he diagonals of quadrilateral QRST intersect at P(-1,3). QRST has vertices at Q(1,7) and R(-4,5). What must be the coordinates of S and T to ensure that QRST is a parallelogram

Sam used his calculator to find cos 1.75. he wrote down cos 1.75 = .999. how could sam recognize that his answer is incorrect?

Find the sum of 4x^{2} -4+6 and -7^{2} +3x+1

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.)