Answer:
vertex = (- 1, 3 )
Step-by-step explanation:
Given a parabola in standard form
y = ax² + bx + c ( a ≠ 0 )
Then the x- coordinate of the vertex is
= -
y = 2x² + 4x + 5 ← is in standard form
with a = 2, b = 4, then
= -
= - 1
Substitute x = - 1 into the equation for corresponding value of y, that is
y = 2(- 1)² + 4(- 1) + 5 = 2 - 4 + 5 = 3
vertex = (- 1, 3 )
P(7,6), Q(1,6), R(4,2)
We have PQ parallel to the x axis. We'll call that the base,
b = 7 - 1 = 6
The altitude is then the y difference h = 6 - 2 = 4
The area is
Answer: 12 square units
In general we can use the shoelace formula for the area of any polygon given coordinates. We write the points like this:
(7,6), (1,6), (4,2)
(1,6), (4,2), (7,6)
The area is then half the absolute value of the sum of the cross products: