Answer:
case a)
----> open up
case b)
----> open down
case c)
----> open left
case d)
----> open right
Step-by-step explanation:
we know that
1) The general equation of a vertical parabola is equal to

where
a is a coefficient
(h,k) is the vertex
If a>0 ----> the parabola open upward and the vertex is a minimum
If a<0 ----> the parabola open downward and the vertex is a maximum
2) The general equation of a horizontal parabola is equal to

where
a is a coefficient
(h,k) is the vertex
If a>0 ----> the parabola open to the right
If a<0 ----> the parabola open to the left
Verify each case
case a) we have

so


so

therefore
The parabola open up
case b) we have

so



therefore
The parabola open down
case c) we have

so



therefore
The parabola open to the left
case d) we have

so



therefore
The parabola open to the right
If a line <span>parallel </span>to one side of a <span>triangle </span>intersects the other two sides of the triangle, then the line divides these two sides proportionally.
1/3 because all you have to do is flip it