PLEASE HELP URGEN

A row operation is performed on a matrix as shown below.

I 2 -1 1 I 4 I. I 0 -3. x I -18 I
I 1 1 1 I 11 I > I 1. 1. 1 I 11 I
I 4. -2 2 I 5 I. I 4 -2 2 I 5 I

What is the value of x?
a. -2
b. -1
c. 0
d. 3

Which expression can be used to determine the slope of the line that passes through the points -6, three and one, -9

Astuntman jumping off a 20-m-high building is modeled by the equation h=20-5t^2, where t is the same in seconds. a high-speed camera is ready to film him between 15m and 10m above the ground. for which interval of time should the camera film him?

Valentina is subtracting from . she finds the lcd to be 15y2. what is valentina's next step?