30 Use the method of completing the square to determine the vertex of f(x) = x² - 14x - 15.
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Answer:
The coordinates of the point b are:
b(x₂, y₂) = (-5, -1)
Step-by-step explanation:
Given
As m is the midpoint, so
m(x, y) = m (-7, -2.5)
The other point a is given by
a(x₁, y₁) = a(-9, -4)
To determine
We need to determine the coordinates of the point b
= ?
Using the midpoint formula
substituting (x, y) = (-7, -2.5), (x₁, y₁) = (-9, -4)
Thus equvating,
Determining the x-coordinate of b
[x₂ + (-9)] / 2 = -7
x₂ + (-9) = -14
x₂ - 9 = -14
adding 9 to both sides
x₂ - 9 + 9 = -14 + 9
x₂ = -5
Determining the y-coordinate of b
[y₂ + (-4)] / 2 = -2.5
y₂ + (-4) = -2.5(2)
y₂ - 4 = -5
adding 4 to both sides
y₂ - 4 + 4 = -5 + 4
y₂ = -1
Therefore, the coordinates of the point b are:
b(x₂, y₂) = (-5, -1)