Answer:
6) y = x^(5/3)
7) B
8) C
10) A
Step-by-step explanation:
6) The fifth root is the same as raising to the 1/5 power, so we can write this in exponent form as:
f(x) = (x^(1/5))³
f(x) = x^(3/5)
To find the inverse, switch x and y and solve for y.
x = y^(3/5)
y = x^(5/3)
7) f(x) = 2√(x − 4) + 8
Switch the x and y and solve for y:
x = 2√(y − 4) + 8
x − 8 = 2√(y − 4)
(x − 8) / 2 = √(y − 4)
(x − 8)² / 4 = y − 4
(x² − 16x + 64) / 4 = y − 4
¼x² − 4x + 16 = y − 4
y = ¼x² − 4x + 20
8) Find the inverse:
x = 5√(y + 3) − 2
x + 2 = 5√(y + 3)
(x + 2) / 5 = √(y + 3)
(x + 2)² / 25 = y + 3
y = -3 + (x + 2)² / 25
The inverse function is an upwards parabola with a vertex at (-2, -3). The best fit is C.
desmos.com/calculator/fbabg5wc8b
10) √(4x − 31) = x − 7
Square both sides:
4x − 31 = (x − 7)²
4x − 31 = x² − 14x + 49
Combine like terms:
0 = x² − 18x + 80
Factor:
0 = (x − 8) (x − 10)
x = 8 or 10
Check for extraneous solutions.
√(4×8 − 31) = 8 − 7
1 = 1
√(4×10 − 31) = 10 − 7
3 = 3
x = 8 and x = 10 are both solutions.
Answer:
We need a sample size of at least 75.
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
So it is z with a pvalue of 
, so 
Now, we find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
The standard deviation is the square root of the variance. So:
With a .95 probability, the sample size that needs to be taken if the desired margin of error is 5 or less is
We need a sample size of at least n, in which n is found when M = 5. So
We need a sample size of at least 75.
Answer:
x=72 and the exterior angle is 154
Step-by-step explanation:
We will call the unknown angle in the triangle y. Angle y and the angle (2x +10) form a straight line so they make 180 degrees.
y + 2x+10 =180
Solve for y by subtracting 2x+10 from each side.
y + 2x+10 - (2x+10) =180 - (2x+10)
y = 180-2x-10
y = 170-2x
The three angles of a triangle add to 180 degrees
x+ y+ 82 = 180
x+ (170-2x)+82 = 180
Combine like terms
-x +252=180
Subtract 252 from each side
-x+252-252 = 180-252
-x = -72
Multiply each side by -1
-1*-x = -72*-1
x=72
The exterior angle is 2x+10. Substitute x=72 into the equation.
2(72)+10
144+10
154
