Answer
2) Option C is correct.
The vertex of the quadratic function is at
x = 6, y = 8.
In coordinate form, the vertex = (6, 8)
4) Option A is correct.
-3 stretches the graph and reflects it about the x-axis.
Step-by-step explanation
2) We are told to find the vertex of the quadratic function. The vertex of a quadratic function is the point at the base of the curve/graph of the function. It is the point where the value of the quadratic function changes sign.
The x-coordinate of this vertex is given as
x = (-b/2a)
The y-coordinate is then obtained from the value of the x-coordinate.
The quadratic function for the question is
y = -5 (x - 6)² + 8
We first need to put the quadratic function in the general form of
y = ax² + bx + c
So, we first simplify the expression
y = -5 (x - 6)² + 8
= -5 (x² - 12x + 36) + 8
= -5x² + 60x - 180 + 8
y = -5x² + 60x - 172
So,
a = -5
b = 60
c = -172
For the vertex
x = (-b/2a)
= [-60/(2×-5)]
= [-60/-10]
= 6
So, if x = 6.
y = -5x² + 60x - 172
y = -5(6²) + 60(6) - 172
y = -5(36) + 360 - 172
y = -180 + 360 - 172
y = 8
So, the vertex of the quadratic function is at
x = 6, y = 8.
In coordinate form, the vertex = (6, 8)
Option C is correct.
4) y = -3(x²)
The graph of x² is a parabola, but multiplying the function x² by -3 transforms the graph.
The 3, because it is greater than 1, stretches or enlarges the graph.
And the minus sign in front of the 3, ,that is, -3 reflects the graph about the x-axis.
So, altogether, -3 stretches the graph and reflects it about the x-axis.
Option A is correct.
Hope this Helps!!!