Im going to keep it simple, the answer is 9
Use photomath ! It's an app that gives you the answer with the explanation and it shows you how it got to the answer !
Which one do you need help with???
To solve y, we need to make y the only value on the left hand side of the equation:

Therefore the value of y = -14+3x.
Hope it helps!
Call M the midpoint. The coordinate of this point is given by....
M=(x1+x2 /2, y1+y2 /2)
So (3,7)=(x1+0 /2, y1+ -5 /2). or
3= x1/2. or x1=6 and
7=y1-5 /2. or 14=y1-5 or y1=19
B is at the point (6,19)