Answer:
Option B: 
Step-by-step explanation:
The parabola has its concavity downwards, so we need a function in the model:
With a negative value of 'a'
The vertex is (0,0), so we have that:
The x-coordinate of the vertex is given by the equation:
So we have a function in the model:
With a < 0
The only option with this format is B:
Answer:
A figure has rotational symmetry if it can be rotated by an angle between 0° and 360° so that the image coincides with the preimage.
Step-by-step explanation:
Pt=6.245cm, working shown in photo
For get the solution of this task, we must make the system of equations.First it: "The quotient between the sum of two numbers and one of them is equal to 3" Let's take two values: a and b.(a+b)/b=3 --- it's will be first equation in our system.
and "The inverse of double the sum of them and equal to 1/6"1/2(a+b)=1/6 it's will be second equation in our system.
Attention at parenthesis.
System(a+b)/b=31/2(a+b)=1/6
by the first equation:(a+b)/b=3a+b=3ba=2b --- we will use this equation for second equation in system
1/2(2b+b)=1/61/3b)=1/63b=6b=2 and a=2b, that's mean a=1.The answer is pair (1;2)
