Assuming you meant the x2 as x squared, then:
(11x+4)(11x-4)
Answer:
When we compare the significance level 
we see that 
so we can reject the null hypothesis at 10% of significance. So the the true mean is difference from 21 at this significance level.
Step-by-step explanation:
Data given and notation
represent the sample mean
represent the population standard deviation
sample size
represent the value that we want to test
represent the significance level for the hypothesis test.
z would represent the statistic (variable of interest)
represent the p value for the test (variable of interest)
State the null and alternative hypotheses.
We need to conduct a hypothesis in order to check if the average age of the evening students is significantly different from 21, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
The statistic is given by:
(1)
Calculate the statistic
We can replace in formula (1) the info given like this:
P-value
Since is a two sided test the p value would be:
Conclusion
When we compare the significance level we see that so we can reject the null hypothesis at 10% of significance. So the the true mean is difference from 21 at this significance level.
We'll first clear a few points.
1. A hyperbola with horizontal axis and centred on origin (i.e. foci are centred on the x-axis) has equation
x^2/a^2-y^2/b^2=1
(check: when y=0, x=+/- a, the vertices)
The corresponding hyperbola with vertical axis centred on origin has equation
y^2/a^2-x^2/b^2=1
(check: when x=0, y=+/- a, the vertices).
The co-vertex is the distance b in the above formula, such that
the distance of the foci from the origin, c satisfies c^2=a^2+b^2.
The rectangle with width a and height b has diagonals which are the asymptotes of the hyperbola.
We're given vertex = +/- 3, and covertex=+/- 5.
And since vertices are situated at (3,0), and (-3,0), they are along the x-axis.
So the equation must start with
x^2/3^2.
It will be good practice for you to sketch all four hyperbolas given in the choices to fully understand the basics of a hyperbola.
Answer: x > 5
Explanation: First we want to look at our variable and ask ourselves what's happening to it. Since 2 is being subtracted from 9x, we always undo addition and subtraction first so we add 2 to both sides.
That gives us 9x > 45.
Now we need to undo multiplication and division. Since 9 is being multiplied by <em>x</em>, to get <em>x</em> by itself, we need to divide by 9 on the left side of the inequality. If we divide by 9 on the left side, we must also divide by 9 on the right side.
This leaves us with <em>x > 5</em> which is the solution to this inequality.
