Which shows a perfect square trinomial?

50 y squared minus 4 x squared
100 minus 36 x squared y squared
16 x squared + 24 x y + 9 y squared
49 x squared minus 70 x y + 10 y squared

The line y = x + passes through (−3, 7) and is parallel to y = 4x − 1.

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

What statement is true? 2x^2-9x+2=-1