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3 years ago

-x+2y=9 -7x-2y=-1 Solve each system by elimination

1 answer:

5 0

X - 2y = - 9
7x + 2y = 1

x - 2y = - 9
(+)
7x + 2y = 1
___________
8x = - 8

x = - 1

- 1 - 2y = - 9
2y = 8
y = 4

i am a mathematics teacher. if anything to ask please pm me

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Steps to solve this-- Find the percent of increase from 380 to 440. Round to the nearest tenth of a percent if necessary. 13.6%

OLga [1]

If 380 would be 100%

Then use rule of 3

380 ______ 100%

440 ______ y

380y = 440×100%

380y = 440 × 1

Dividing both the sides by 380

y = 440/380

y = 1,158

Let's multiplity "y" by 100

y = 115,8%

As we did have 100% initially

Then the increase will be

The increase = 115,8% -100%

= 15,8%

This would your answer

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The volume of a cone is 3πx3 cubic units and its height is x units. Which expression represents the radius of the cone’s base, i

dalvyx [7]

Answer:

Step-by-step explanation:

<u>The Volume of a Cone</u>

The volume of a cone of radius r and height h is:

$\displaystyle V=\frac{1}{3}\pi hr^2$

We are given the volume of a cone is

$V=3\pi x^3$

Equating:

$\displaystyle \frac{1}{3}\pi hr^2=3\pi x^3$

Multiplying by 3:

$\pi hr^2=9\pi x^3$

Simplifying by pi:

$hr^2=9 x^3$

Since h=x:

$xr^2=9 x^3$

Dividing by x:

$r^2=9 x^2$

Taking square roots:

$r=\sqrt{9 x^2}=3x$

Thus: r=3x

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