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2 years ago

Y is inversley proportionaly to x. when y=7, x=9

Mathematics

1 answer:

mrs_skeptik [129]2 years ago

8 0

The equation is y = 63/x

And y = 3 when x=21

Step-by-step explanation:

When y varies inversely with x, The inverse proportion is given by:

y ∝1/x

When the proportionality symbol is removed, a constant of proportionality is introduced

$y = \frac{k}{x}$

Putting y = 7 and x = 9

$7 = \frac{k}{9}\\k = 9*7\\k = 63$

So,

$y = \frac{63}{x}$

Putting x =21

$y = \frac{63}{21}\\y = 3$

Hence,

The equation is y = 63/x

And y = 3 when x=21

Keywords: Proportion, variables

Learn more about proportion at:

#LearnwithBrainly

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Factor this x^3 + 27

masya89 [10]

(x+3)(x^2-3x+9)

this gets the x^3 while the 3x cancels out and 3*9=27

hope this helps although i didn't explain very well :)

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2 years ago

There are 11 students on the tennis team. The coach selects 3 of them to go to atennis clinic. In how many ways can he choose 3

Komok [63]

Answer:

165 ways

Step-by-step explanation:

Selection deals with combination

There are a total of 11 from which 3 are to be selected

11C3 = 11!/3!(11-3)!

= 11!/(3!x8!)

=(11x10x9x8!)/(3x2x8!)

=11x10x9/6

=11x5x3 = 165 ways

8 0

2 years ago

Please find which quadratic equation matches the graph with work attached

lesya [120]

Answer:

Step-by-step explanation:

Firstly, we know that the function must be negative due to its shape. This means that the answer cannot be B

Next we can use the equation $x=\frac{-b}{2a}$ that is used in order to find the vertex of the parabola.

$f(x)=-x^2+6x+7\\a=-1,b=6,c=7\\\\x=\frac{-6}{-2} \\x=3$

As the vertex is at x=3 on the graph, this one could be a contender.

$f(x)=-x^2+6x-7\\a=-1,b=6, c=-7\\\\x=\frac{-6}{-2} \\\\x=3$

This also could be the equation

$f(x)=-x^2-6x-7\\\\a=-1, b=-6, c=-7\\\\x=\frac{6}{-2} \\\\x=-3$

This rules option D out.

For this last step, we can look at where the zeroes would be for each equation. (These values are irrational, so we cannot look at specific number)

$f(x)=-(x^2-6x-7)$

As this equation has a negative value for c, this means that one zero must be positive and the other must be negative.

This means that option A can be ruled out

$f(x)=-(x^2-6x+7)$

As this equation has a positive value for c, this means that both of the zeroes must be positive. This means that it is the only one that fits all of the criteria.

7 0

2 years ago

Is the number 5 prime, composite, or neither?

OlgaM077 [116]

Answer:

A number that is divisible only by itself and 1

therefore 5 is a prime number

3 0

2 years ago

Read 2 more answers

A rectangular prism has a length of 212 centimeters, a width of 212 centimeters, and a height of 5 centimeters. Justin has a sto

BlackZzzverrR [31]

Answer:

$3.75\ cm^{3}$ or $3\frac{3}{4}\ cm^{3}$

Step-by-step explanation:

step 1

Find the volume of the rectangular prism

we know that

The volume of a rectangular prism is

$V=LWH$

In this problem we have

$L=2\frac{1}{2}\ cm=\frac{2*2+1}{2}=\frac{5}{2}\ cm$

$W=2\frac{1}{2}\ cm=\frac{2*2+1}{2}=\frac{5}{2}\ cm$

$H=5\ cm$

substitute in the formula

$V=(\frac{5}{2})(\frac{5}{2})(5)=\frac{125}{4}=31.25\ cm^{3}$

step 2

Find the difference between the volume of the prism and the volume of the storage container

$35\ cm^{3}-31.25\ cm^{3}=3.75\ cm^{3}$

$3.75=3\frac{3}{4}\ cm^{3}$

3 0

3 years ago