Answer:
Step-by-step explanation:
If you plot this point and the directrix on a coordinate plane, you can see that the directrix is 1/4 of a unit below the vertex. Since, by nature, a parabola opens in the direction opposite the directrix and "hugs" the focus, this is a positive x-squared parabola (meaning it opens upwards). The formula for this type of a parabola is, in vertex form,
where p is distance (in units) between the vertex and the directrix and h and k are the coordinates of the vertex. For us, p = .25, h = 7, and k = -6. Filling in our formula:
Simplify the left side to
which simplifies, in its entirety, to
120 divided by 8= 15
15 students per year is the answer.
All you have to do is do the distributive property. So, for the first one you would do 5 times x which equals 5x and then you would do 5 times 4 which equals twenty. All you are left with is the addition sign. Your full equation now would be 5x+20
The double implication "if and only if" is graphically represented by an arrow pointing in both direction, so the correct writing is