Check the picture below, so the parabola looks more or less like so, with a vertex at (0 , -7), let's recall the vertex is half-way between the focus point and the directrix.
so this horizontal parabola opens up to the left-hand-side, meaning that the "P" distance is a negative value.
Answer: 220
<u>Step-by-step explanation:</u>
Children (x): $2
Teens (y): $3,
Adults: (z): $5
Quantity: x + y + z = 570 ⇒ x + + z = 570 ⇒ 1.75x + z = 570
Cost: 2x + 3y + 5z = 1950 ⇒ 2x + 3 + 5z = 1950 ⇒ 2x + 2.25x + 5z = 1950 ⇒ 4.25x + 5z = 1950
Qty: 1.75x + z = 570 → 5(1.75x + z = 570) → 8.75x + 5z = 2850
Cost: 4.25x + 5z = 1950 → -1(4.25x + 5z = 1950 → <u> -4.25x - 5z</u> = <u>-1950 </u>
4.50x = 900
x = 200
Teens (y):
y =
=
= 150
Quantity: x + y + z = 570
200 + 150 + z = 570
350 + z = 570
z = 220