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3 years ago

Use the distributive property to write an expression that is equivalent to 12+4x.

Mathematics

1 answer:

Sav [38]3 years ago

7 0

Answer:

12 + 4x= (6 x 2) + (2x x 2)

Step-by-step explanation:

this is the pic

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A norman window is constructed by adjoining a semicircle to the top of an ordinary rectangular. Find the dimensions of a norman

Yanka [14]

Answer:

$W\approx 8.72$ and $L\approx 15.57$ .

Step-by-step explanation:

Please find the attachment.

We have been given that a norman window is constructed by adjoining a semicircle to the top of an ordinary rectangular. The total perimeter is 38 feet.

The perimeter of the window will be equal to three sides of rectangle plus half the perimeter of circle. We can represent our given information in an equation as:

$2L+W+\frac{1}{2}(2\pi r)=38$

We can see that diameter of semicircle is W. We know that diameter is twice the radius, so we will get:

$2L+W+\frac{1}{2}(2r\pi)=38$

$2L+W+\frac{\pi}{2}W=38$

Let us find area of window equation as:

$\text{Area}=W\cdot L+\frac{1}{2}(\pi r^2)$

$\text{Area}=W\cdot L+\frac{1}{2}(\pi (\frac{W}{2})^2)$

$\text{Area}=W\cdot L+\frac{\pi}{2}(\frac{W}{2})^2)$

$\text{Area}=W\cdot L+\frac{\pi}{2}(\frac{W^2}{4})$

$\text{Area}=W\cdot L+\frac{\pi}{8}W^2$

Now, we will solve for L is terms W from perimeter equation as:

$L=38-(W+\frac{\pi }{2}W)$

Substitute this value in area equation:

$A=W\cdot (38-W-\frac{\pi }{2}W)+\frac{\pi}{8}W^2$

Since we need the area of window to maximize, so we need to optimize area equation.

$A=W\cdot (38-W-\frac{\pi }{2}W)+\frac{\pi}{8}W^2$

$A=38W-W^2-\frac{\pi }{2}W^2+\frac{\pi}{8}W^2$

Let us find derivative of area equation as:

$A'=38-2W-\frac{2\pi }{2}W+\frac{2\pi}{8}W$

$A'=38-2W-\pi W+\frac{\pi}{4}W$

$A'=38-2W-\frac{4\pi W}{4}+\frac{\pi}{4}W$

$A'=38-2W-\frac{3\pi W}{4}$

To find maxima, we will equate first derivative equal to 0 as:

$38-2W-\frac{3\pi W}{4}=0$

$-2W-\frac{3\pi W}{4}=-38$

$\frac{-8W-3\pi W}{4}=-38$

$\frac{-8W-3\pi W}{4}*4=-38*4$

$-8W-3\pi W=-152$

$8W+3\pi W=152$

$W(8+3\pi)=152$

$W=\frac{152}{8+3\pi}$

$W=8.723210$

$W\approx 8.72$

Upon substituting $W=8.723210$ in equation $L=38-(W+\frac{\pi }{2}W)$ , we will get:

$L=38-(8.723210+\frac{\pi }{2}8.723210)$

$L=38-(8.723210+\frac{8.723210\pi }{2})$

$L=38-(8.723210+\frac{27.40477245}{2})$

$L=38-(8.723210+13.70238622)$

$L=38-(22.42559622)$

$L=15.57440378$

$L\approx 15.57$

Therefore, the dimensions of the window that will maximize the area would be $W\approx 8.72$ and $L\approx 15.57$ .

8 0

3 years ago

(Warning this is an extremely hard question)

lesya [120]

I don't have my glasss on and there are too many 1's which are messing with my eyes but all i have to say is PEMDAS
bonus question - i used to like school but at this point i just want to graduate

4 0

3 years ago

Please help asap, will mark brainlest. Thanks

mixer [17]

Answer:

4x^2 + 4 - 5x + x - 2x^2 + 8

= (4x^2 - 2x^2) + (x - 5x) + (4 + 8)

= 2x^2 - 4x + 12

=> D is correct

2x^2 + 6x - 7x + 8 - 3x^2 + 1

= (2x^2 - 3x^2) + (6x - 7x) + (1 + 8)

= -x^2 - x + 9

=> C is correct

B is correct (4 and 3)

Hope this helps!

3 0

3 years ago

A dripping tap loses water at a rate of 5mL a minute.

STatiana [176]

1 liter = 1000mL

Divide 1000mL by mL per minute:

1000 / 5 = 200 minutes ( 3 hours and 20 minutes)

7 0

3 years ago

Distributive property for 4 2/5x10?<br><br> Distributive property for 26×2 1/2

Nimfa-mama [501]

4 2/5 x 10 = 4x 10 + 2/5 * 10
40 + 4 = 44

26 x 2 1/2 = 26 x 2 + 26 * 1/2
52 + 13 = 65

5 0

3 years ago