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2 years ago

9

[Will award brainliest if correct!] It takes a painter and his friend 8 hours to paint a room. if the painter was working alone,

it would take him 12 hours less than if his friend was working alone. How long does it take the painter to paint the room by himself?

1 answer:

Keith_Richards [23]2 years ago

5 0

Answer:

it would take him 10 hours

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How do I factor x^4-5x^2+6?

Vilka [71]

Answer:

$=(x^2-3)(x^2-2)$

Step-by-step explanation:

So we have the expression:

$x^4-5x^2+6$

And we wish to factor it.

First, let's make a substitution. Let's let u be equal to x². Therefore, our expression is now:

$=u^2-5u+6$

This is a technique called quadratic u-substitution. Now, we can factor in this form.

We can use the numbers -3 and -2. So:

$=u^2-2u-3u+6$

For the first two terms, factor out a u.

For the last two terms, factor out a -3. So:

$=u(u-2)-3(u-2)$

Grouping:

$=(u-3)(u-2)$

Now, substitute back the x² for u:

$=(x^2-3)(x^2-2)$

And this is the simplest form.

And we're done!

3 0

2 years ago

Find the standard equation of a sphere that has diameter with the end points given below. (3,-2,4) (7,12,4)

DiKsa [7]

Answer:

The standard equation of the sphere is $(x-5)^{2} + (y-5)^{2} + (z-4)^{2} = 53$

Step-by-step explanation:

From the question, the end point are (3,-2,4) and (7,12,4)

Since we know the end points of the diameter, we can determine the center (midpoint of the two end points) of the sphere.

The midpoint can be calculated thus

Midpoint = $(\frac{x_{1} + x_{2} }{2}, \frac{y_{1} + y_{2} }{2}, \frac{z_{1} + z_{2} }{2})$

Let the first endpoint be represented as $(x_{1}, y_{1}, z_{1})$ and the second endpoint be $(x_{2}, y_{2}, z_{2})$ .

Hence,

Midpoint = $(\frac{x_{1} + x_{2} }{2}, \frac{y_{1} + y_{2} }{2}, \frac{z_{1} + z_{2} }{2})$

Midpoint = $(\frac{3 + 7 }{2}, \frac{-2+12 }{2}, \frac{4 + 4 }{2})$

Midpoint = $(\frac{10 }{2}, \frac{10}{2}, \frac{8 }{2})\\$

Midpoint = $(5, 5, 4)$

This is the center of the sphere.

Now, we will determine the distance (diameter) of the sphere

The distance is given by

$d = \sqrt{(x_{2} - x_{1})^{2} +(y_{2} - y_{1})^{2} + (z_{2}- z_{1})^{2} }$

$d = \sqrt{(7 - 3)^{2} +(12 - -2)^{2} + (4- 4)^{2}$

$d = \sqrt{(4)^{2} +(14)^{2} + (0)^{2}$

$d = \sqrt{16 +196 + 0$

$d =\sqrt{212}$

$d = 2\sqrt{53}$

This is the diameter

To find the radius, r

From $Radius = \frac{Diameter}{2}$

$Radius = \frac{2\sqrt{53} }{2}$

∴ $Radius = \sqrt{53}$

r = $\sqrt{53}$

Now, we can write the standard equation of the sphere since we know the center and the radius

Center of the sphere is $(5, 5, 4)$

Radius of the sphere is $\sqrt{53}$

The equation of a sphere of radius r and center $(h,k,l)$ is given by

$(x-h)^{2} + (y-k)^{2} + (z-l)^{2} = r^{2}$

Hence, the equation of the sphere of radius $\sqrt{53}$ and center $(5, 5, 4)$ is

$(x-5)^{2} + (y-5)^{2} + (z-4)^{2} = \sqrt{(53} )^{2}$

$(x-5)^{2} + (y-5)^{2} + (z-4)^{2} = 53$

This is the standard equation of the sphere

6 0

2 years ago

my sister wants to watch 6 star wars movies ,if each movie. is 2 hours , how long will it take her to watch all of the movies?

poizon [28]

12 hours, 6 x 2 = 12.

4 0

2 years ago

Read 2 more answers

I need accurate answer please because this is the last attempt

matrenka [14]

Answer:

I'm not very sure, however I think you have to replace the sign - for a +.

Step-by-step explanation:

7 + 4√13

3 0

3 years ago

What is the unit rate for 6 pack soda for $7.96

Allisa [31]

7.96 / 6 = 1.33 <== unit rate

6 0

3 years ago