Which of the follwong numbers must be added to complete the square in the equation below?

x^2+6x-19=23

a.19 b.3 c.-9 d.9

The vertex of this parabola is at (-2,-3). when the x-value is -1, the y-value is -5. what is the coefficient of the squared expression in the parabola's equation?

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

When x = 3 and y = 5, by how much does the value of 3x2 – 2y exceed the value of 2x2 – 3y ?