
There are 2 roots so the only way to complete the square is,
![y=2x^2+8x-9\\y=2[(x^2+4x)]-9\\y=2[(x^2+4x+4)-4]-9\\y=2[(x+2)^2-4]-9\\y=2(x+2)^2-8-9\\y=2(x+2)^2-17](https://tex.z-dn.net/?f=y%3D2x%5E2%2B8x-9%5C%5Cy%3D2%5B%28x%5E2%2B4x%29%5D-9%5C%5Cy%3D2%5B%28x%5E2%2B4x%2B4%29-4%5D-9%5C%5Cy%3D2%5B%28x%2B2%29%5E2-4%5D-9%5C%5Cy%3D2%28x%2B2%29%5E2-8-9%5C%5Cy%3D2%28x%2B2%29%5E2-17)
Just factor 2 out of 2x^2+8x (just ignore the -9) then find the number that will make the terms be able to complete the square.
then complete the square and multiply 2 inside the brackets.
subtraction as you already get the vertex form and know how to complete the square.
Vertex Form: 
<u></u><u>The correct answer is 47.5%, or 0.475.</u>
Explanation:
The empirical rule states that in any normal distribution:
68% of data will fall within 1 standard deviation of the mean;
95% of data will fall within 2 standard deviations of the mean; and
99.7% of data will fall within 3 standard deviations of the mean.
The mean is 500 and the standard deviation is 100. This means that 700 is 2 standard deviations away from the mean:
(700-500)/100=200/100=2.
We know that 95% of data will fall within 2 standard deviations from the mean. However, included in the 95% is data less than the mean and greater than the mean. Since we are only concerned with the scores from 500 to 700, we only want the half that is greater than the mean:
95/2 = 47.5%, or 0.475.
Answer:
y/x
Step-by-step explanation:
If x is proportional to y, then:
y = kx, where k is a constant
This can be rearranged to give:
k = y/x
As mentioned, k is a constant, therefore, the answer is y/x
Answer:
D. 21.
Step-by-step explanation:
The general form of the equation of a circle is:
(x - a)^2 + (y - b)^2 = r^2 where r is the radius.
Comparing:
(x + 5)^2 + (y + 7)^2 = 21^2
So r^2 = 21^2
making r = √21^2
= 21.
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