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QveST [7]
3 years ago
8

M is directly proportional to r cubed when r = 4, m = 160. Find the value of r when m = 540

Mathematics
1 answer:
Anarel [89]3 years ago
5 0

Answer:

r = 6

Step-by-step explanation:

Given that M is directly proportional to r³ then the equation relating them is

M = kr³ ← k is the constant of proportionality

To find k use the condition r = 4 when M = 160

k = \frac{M}{r^3} = \frac{160}{64} = 2.5, so

M = 2.5r³ ← equation of proportionality

When M = 540, then

540 = 2.5 r³ ( divide both sides by 2.5 )

216 = r³ ( take the cube root of both sides )

r = \sqrt[3]{216} = 6

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This is already late but please help
Nostrana [21]

Answer: 12.5

Step-by-step explanation:

x/10 = 10/8

reduce the fraction with 2

x/10=5/4

simplify the equation using cross-multiplication

4x=50

divide both sides by 4

x=25/2

or

x=12.5

3 0
2 years ago
I need help or I will faill this
kari74 [83]

Answer:

-4x2 + 3x - 225

 ———————————————

        3    

Step-by-step explanation:

Step  1  :

               4

Simplify   —

                3

Equation at the end of step  1  :

        4            

 (x -  (— • x2)) -  75

        3            

Step  2  :

Equation at the end of step  2  :

       4x2      

 (x -  ———) -  75

        3      

Step  3  :

Rewriting the whole as an Equivalent Fraction :

3.1   Subtracting a fraction from a whole

Rewrite the whole as a fraction using  3  as the denominator :

         x     x • 3

    x =  —  =  —————

         1       3  

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 :

3.2       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:

x • 3 - (4x2)     3x - 4x2

—————————————  =  ————————

      3              3    

Equation at the end of step  3  :

 (3x - 4x2)    

 —————————— -  75

     3          

Step  4  :

Rewriting the whole as an Equivalent Fraction :

4.1   Subtracting a whole from a fraction

Rewrite the whole as a fraction using  3  as the denominator :

         75     75 • 3

   75 =  ——  =  ——————

         1        3    

Step  5  :

Pulling out like terms :

5.1     Pull out like factors :

  3x - 4x2  =   -x • (4x - 3)  

Adding fractions that have a common denominator :

5.2       Adding up the two equivalent fractions

-x • (4x-3) - (75 • 3)     -4x2 + 3x - 225

——————————————————————  =  ———————————————

          3                       3        

Step  6  :

Pulling out like terms :

6.1     Pull out like factors :

  -4x2 + 3x - 225  =   -1 • (4x2 - 3x + 225)  

Trying to factor by splitting the middle term

6.2     Factoring  4x2 - 3x + 225  

The first term is,  4x2  its coefficient is  4 .

The middle term is,  -3x  its coefficient is  -3 .

The last term, "the constant", is  +225  

Step-1 : Multiply the coefficient of the first term by the constant   4 • 225 = 900  

Step-2 : Find two factors of  900  whose sum equals the coefficient of the middle term, which is   -3 .

     -900    +    -1    =    -901  

     -450    +    -2    =    -452  

     -300    +    -3    =    -303  

     -225    +    -4    =    -229  

     -180    +    -5    =    -185  

     -150    +    -6    =    -156  

For tidiness, printing of 48 lines which failed to find two such factors, was suppressed

Observation : No two such factors can be found !!

Conclusion : Trinomial can not be factored

Final result :

 -4x2 + 3x - 225

 ———————————————

        3        

7 0
3 years ago
Suppose the speeds of vehicles traveling on a highway are normally distributed and have a known population standard deviation of
erik [133]

Answer:

2.88

Step-by-step explanation:

Data provided in the question

\sigma = Population standard deviation = 7 miles per hour

Random sample = n = 32 vehicles

Sample mean = \bar X = 64 miles per hour

98% confidence level

Now based on the above information, the alpha is

= 1 - confidence level

= 1 - 0.98

= 0.02

For \alpha_1_2 = 0.01

Z \alpha_1_2 = 2.326

Now the margin of error is

= Z \alpha_1_2 \times \frac{\sigma}{\sqrt{n}}

= 2.326 \times \frac{7}{\sqrt{32}}

= 2.88

hence, the margin of error is 2.88

5 0
3 years ago
Evaluate g(n- 7) if g(x) = x^2-6/7x
noname [10]

Step-by-step explanation:

g(n-7) = (n-7) ^2-6/7 (n-7) = n^2 -14n+49-6/7 n +6= n^2-104/7 n +55

5 0
3 years ago
Whats nine and eight four hundredths in standard from
Nookie1986 [14]
Do you mean 'nine and eighty four hundredths' in standard form? If so, it will be:

9.84
7 0
3 years ago
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