Answer:
18
Step-by-step explanation:
f(x) = 2(1/3)^x
[x = -2]
f(-2) = 2(1/3)⁻²
= 2(9)
= 18
8/x+9-(2/x-3)=0
Step by step solution :
Step 1 :
2
Simplify —
x
Equation at the end of step 1 :
8 2
(— + 9) - (— - 3) = 0
x x
Step 2 :
Rewriting the whole as an Equivalent Fraction :
2.1 Subtracting a whole from a fraction
Rewrite the whole as a fraction using x as the denominator :
3 3 • x
3 = — = —————
1 x
Equivalent fraction : The fraction thus generated looks different but has the same value as the whole
Common denominator : The equivalent fraction and the other fraction involved in the calculation share the same denominator
Adding fractions that have a common denominator :
2.2 Adding up the two equivalent fractions
Add the two equivalent fractions which now have a common denominator
Combine the numerators together, put the sum or difference over the common denominator then reduce to lowest terms if possible:
2 - (3 • x) 2 - 3x
——————————— = ——————
x x
Equation at the end of step 2 :
8 (2 - 3x)
(— + 9) - ———————— = 0
x x
Step 3 :
8
Simplify —
x
Equation at the end of step 3 :
8 (2 - 3x)
(— + 9) - ———————— = 0
x x
Step 4 :
Rewriting the whole as an Equivalent Fraction :
4.1 Adding a whole to a fraction
Rewrite the whole as a fraction using x as the denominator :
9 9 • x
9 = — = —————
1 x
Adding fractions that have a common denominator :
4.2 Adding up the two equivalent fractions
8 + 9 • x 9x + 8
————————— = ——————
x x
Equation at the end of step 4 :
(9x + 8) (2 - 3x)
———————— - ———————— = 0
x x
Step 5 :
Adding fractions which have a common denominator :
5.1 Adding fractions which have a common denominator
Combine the numerators together, put the sum or difference over the common denominator then reduce to lowest terms if possible:
(9x+8) - ((2-3x)) 12x + 6
————————————————— = ———————
x x
Step 6 :
Pulling out like terms :
6.1 Pull out like factors :
12x + 6 = 6 • (2x + 1)
Equation at the end of step 6 :
6 • (2x + 1)
———————————— = 0
x
Step 7 :
When a fraction equals zero :
7.1 When a fraction equals zero ...
Where a fraction equals zero, its numerator, the part which is above the fraction line, must equal zero.
Now,to get rid of the denominator, Tiger multiplys both sides of the equation by the denominator.
Here's how:
6•(2x+1)
———————— • x = 0 • x
x
Now, on the left hand side, the x cancels out the denominator, while, on the right hand side, zero times anything is still zero.
The equation now takes the shape :
6 • (2x+1) = 0
Equations which are never true :
7.2 Solve : 6 = 0
This equation has no solution.
A a non-zero constant never equals zero.
Answer:
$75.60
Step-by-step explanation:
First, find the total cost without tax:
42 + 28
= 70
Then, to find the price with sales tax, multiply this by 1.08:
70(1.08)
= 75.6
So, the total cost of her purchases was $75.60
The confidence interval for the mean usage of water is (18.7,20.5).
Given population standard deviation of 2.4, mean of 19.5 gallons per day and confidence interval of 98%.
We have to find the confidence interval for the mean usage of water.
To find out the confidence interval we have to first find margin of error.
μ=19.5
σ=2.4
α=0.98
α/2=0.49
We have to find the z value for the p value 0.49 which is z=2.33
Margin of error=z*μ/
=2.33*19.5/
=0.82
lower level=mean -m
=19.5-0.82
=18.68
after rounding upto 1 decimal
=18.7
upper mean = mean+m
=19.5+0.82
=20.52
Hence the confidence interval for the usage of water is (18.7,20.52).
Learn more about margin of error at brainly.com/question/10218601
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