Answer:
A normal distribution or z-test is used to construct a confidence interval.
Step-by-step explanation:
We are given the following in the question:
Sample mean, 
= $3120
Sample size, n = 40
Population standard deviation, σ = $677
The distribution of earnings of college is a normal distribution.
Conditions:
- Since we are given the population standard deviation and the the sample size is also greater than 30.
Conclusion:
Thus, we use a normal distribution or z-test to construct a confidence interval.
Hope this is a help for u
3x
30
1. 130°
I don't remember too many specifics from my past math classes, but I always remembered this because that is an upside-down mirror of the 130° angle.
2. 50°
A straight line is 180°, and 180 - 130 = 50.
the values of x are -7/5 and -7/8 .
Solve either equation for either variable. Since the second one has y on its own, the easiest choice is to solve that for y.
-5x + y = 13 ⇒ y = 5x + 13
Now substitute this into the other equation to eliminate y and rewrite it entirely in terms of x :
-3x + 3y = 3 ⇒ -3x + 3 (5x + 13) = 3
Simplify and solve for x :
-3x + 15x + 39 = 3
12x = -36
x = -3
Substitute this into either original equation to solve for y. Plugging x = -3 into the first equation would give
-3 (-3) + 3y = 3
9 + 3y = 3
3y = -6
y = -2
So the solution to the system of equations is (x, y) = (-3, -2).
