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2 years ago

4x + 3y = 6 3x + 5y = -1 Solve the simultaneous equations. y= z=

Mathematics

1 answer:

Kisachek [45]2 years ago

4 0

Answer:

x=3, y= -2

Step-by-step explanation:

Multiplying :

(4x+3y =6)*-3

(3x+5y =-1)*4

-12x -9y= -18

12x+20y= -4

Add the equations

20y-9y = -4-18

11y = -22

y= -22/11 = -2

3x +5* -2= -1

3x -10 = -1

3x = 10-1

x= 9/3 =3

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The region bounded by the given curves is rotated about the specified axis. Find the volume V of the resulting solid by any meth

Lubov Fominskaja [6]

Answer:

$\frac{128\pi}{3}$ cubic units

Step-by-step explanation:

We are given that a region bounded by a curves $x=(y-7)^2$

x=4 and about y=5

We have to find the value of volume of the resulting solid

To find the volume of resulting solid we are using cylinder method

Substitute the values of x then we get

$(y-7)^2=4$

$y-7=\pm2$

y-7=2 and y-7=-2

y=7+2=9 and y=-2+7=5

Radius of cylinder =r=y-5

and height =h= $4-(y-7)^2=4-y^2-49+14 y=-y^2+14 y -45$

Using cylinder method and integrate along y -axis from y=5 to y=9

Volume = $\int_{a}^{b}2\pi r h dy=\int_{5}^{9}2\pi(y-5)(-y^2+14 y -45) dy$

volume= $2\pi\int_{5}^{9}(-y^3+19y^2-115y+225)dy$

Volume = $2\pi[-\frac{y^4}{4}+19\frac{y^3}{3}-115\frac{y^2}{2}+225y]^9_5$

Volume = $2\pi[-\frac{6561}{4}+\frac{625}{4}+19(\frac{729-125}{3})-115(\frac{81-25}{2})+225(9-5)]$

Volume= $2\pi(-1484+\frac{11476}{3}-3220+900)$

Volume = $2\pi(\frac{11476}{3}-3804)$

Volume = $2\pi(\frac{11476-11412}{3})=\frac{128\pi}{3}$

Hence, volume of resulting solid = $\frac{128\pi}{3}$ cubic units

3 0

2 years ago

Tim is clearing brush from a large piece of land. The table shows how many acres he has cleared over time. Tim clears the same a

Elena-2011 [213]

Answer:

first box is 3 and second is 2 2/3

4 0

2 years ago

Pls help! evaluate the function for x=3a.

Musya8 [376]

The answer is choice C .

5 0

2 years ago

Javier and his friends go out to eat. The restaurant they chose automatically adds a 15% gratuity to their food bill since they

siniylev [52]

well, we know that 213.90 includes the 15% gratuity, so if the meal price was say "x", namely that is the 100%, and we add 15% to that, then 100% + 15% = 115%, so 213.90 is really the 115%.

now, if 213.90 is the 115.%, what is "x"? the 100%.

$\bf \begin{array}{ccll} amount&\%\\ \cline{1-2} 213.90&115\\ x&100 \end{array}\implies \cfrac{213.9}{x}=\cfrac{115}{100}\implies 21390=115x \\\\\\ \cfrac{21390}{115}=x\implies 186=x$

so since we know the meal without the tip is 186 bucks, the tip was then 213.90 - 186 = 27.90.

but they got extra potato wedges with butter and the waitress was wearing her best hat, they added $20 more, so the tip ended up as 27.90 + 20 = 47.90.

now, if the cost of the meal was $186 and that is the 100%, what is 47.90 off of it in percentage?

$\bf \begin{array}{ccll} amount&\%\\ \cline{1-2} 186&100\\ 47.90&x \end{array}\implies \cfrac{186}{47.90}=\cfrac{100}{x}\implies 186x=4790 \\\\\\ x=\cfrac{4790}{186}\implies x\approx \stackrel{\%}{25.75}$

7 0

2 years ago

Read 2 more answers

25/4=x/10 <br>please help thanks

Marta_Voda [28]

Answer:

125/2 or 62.5 or 62 1/2 (x=)

Step-by-step explanation:

25/4=x/10 multiply everything by 20

25*20/4=20x/10 simplify

25*5=2x simplify

125=2x divide on both sides

125/2 or 62.5 or 62 1/2=x

7 0

3 years ago