Please select the best answers from a-d.
1 answer:
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Answer:
see below
Step-by-step explanation:
The ratio of terms that are two terms apart (s4 and s6) is the square of the common ratio:
s6/s4 = r^2
r = √(8/18)
r = 2/3 . . . . . matches choices A and C
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Using the formula for the general term, we now know enough to find the first term:
sn = s1·r^(n-1)
s4 = s1·(2/3)^(4-1)
Using s4 = 18 and multiplying by (2/3)^-3, we get ...
18·(2/3)^-3 = s1 = 18·27/8
s1 = 243/4 . . . . . matches choice A
we have
This is a vertical parabola open upward
The axis of symmetry is equal to the x-coordinate of the vertex
The vertex is the point (h,k)
the equation of the axis of symmetry is
In this problem
so the x-coordinate of the vertex is
<u>Convert the quadratic equation in vertex form</u>
Group terms that contain the same variable, and move the constant to the opposite side of the equation
Factor the leading coefficient
Complete the square. Remember to balance the equation by adding the same constants to each side
Rewrite as perfect squares
remember that
so
substitute in the equation
therefore
<u>the answer is</u>