How can you tell that x2 - 19x + 90 is not a perfect square trinomial?

Factor. 8x2y2 – 4x2y – 12xy 4(8x2y2 – x – 12xy) 4(2xy – 4x2y – 12xy) 4x2y2(2xy – xy –3) 4xy(2xy – x – 3)

Which fraction below is equivalent to 10/12?

Tom wants to order tickets online so that he and three of his friends can go to a water park the cost of the tickets is 16.00 per person there is also a 2.50 one-time service fee for ordering tickets online write an expression in term of n that represents the cost for n ordering tickets online