For a) The center of the hyperbola is at the intersection of the two asymptotes. This is the point (-4,-2)
Since the vertex at (-4,0) is above this point, we have y orientation. From this, the equation will be of the form
-a (x + 4)2 + b (y + 2)2 = 1 for some a and b
Plugging in (-4,0) shows that b = 1/4
Demanding that y = x/2 be an asymptote shows that a = 1/16 , so finally
-(1/16) (x +4)2 + (1/4) (y +2)2 = 1
For b) The center is at (0,0) so the equation will be
a x2 - b y2 = 1 for some a and b.
Plugging in (2,0) shows that a = 1/4 Plugging in (4, 5 sqrt(3)) leads to b = 1/25 , so
(1/4) x2 - (1/25) y2 = 1