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3 years ago

Can someone solve these 2 problems ? 9 and 8

Mathematics

2 answers:

siniylev [52]3 years ago

5 0

I just answered that on someone elses. the last one is 4x+y+5z=3

answer the other one on the online algebra calcultor

Dvinal [7]3 years ago

5 0

$\begin{bmatrix}x+y+z=5\\ x-y+2z=-4\\ 4x+y+z=2\end{bmatrix}
\\\\
*x+y+z=5
\\y=5-x-z
\\\\ *4x+y+z=2
\\4x+(5-x-z)+z=2
\\4x+5-x-z+z=2
\\4x-x+5=2
\\3x+5=2
\\3x=2-5
\\3x=-3
\\\\x= \frac{-3}{3} 
\\\\x=-1$

$*x-y+2z=-4
\\x-(5-x-z)+2z=-4
\\x-5+x+z+2z=-4
\\x+x+z+2z-5=-4
\\2x+3z-5=-4
\\2x+3z=-4+5
\\2x+3z=1
\\2(-1)+3z=1
\\-2+3z=1
\\3z=1+2
\\3z=3
\\\\z= \frac{3}{3} 
\\\\z=1$

$*x+y+z=5
\\(-1)+y+(1)=5
\\-1+1+y=5
\\y=5$

x = -1
y = 5
z = 1

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Answer for brainliest

Vikentia [17]

The answer is c

25/5 is 5

So 5>4

3 0

3 years ago

It takes a train 60 seconds to completely drive through a bridge of 1260 m, and 90 seconds to completely drive through a tunnel

Olegator [25]

The length of train is 120 meters

The speed of train is 25 meter per second

Solution:

The speed is given by formula:

$speed = \frac{distance}{time}$

Given that,

It takes a train 60 seconds to completely drive through a bridge of 1260 m

And 90 seconds to completely drive through a tunnel of 2010 m

Let the length of the train be "x"

The total distance travelled by the train across the bridge is given by:

total distance = x + 1260 + x = 2x + 1260

[ here we use x + x to represent that train completely drives through bridge ]

The time taken is given as 60 seconds

Therefore, the speed is given as:

$speed = \frac{2x+ 1260}{60}$

The total distance travelled by the train through the tunnel is given by:

total distance = x + 2010 + x = 2x + 2010

The time taken is given as 90 seconds

Therefore, the speed is given as:

$speed = \frac{2x+ 2010}{90}$

The speed of the train was the same in both cases.

Equate both speeds

$\frac{2x+ 1260}{60} = \frac{2x+ 2010}{90}$

$\frac{x+630}{30} = \frac{x+1005}{45}$

$45(x+630) = 30(x+1005)\\\\45x + 28350 = 30x + 30150\\\\45x - 30x = 30150 - 28350\\\\15x = 1800\\\\x = 120$

Thus length of train is 120 meters

Find the speed of train:

$speed = \frac{2x+ 1260}{60}\\\\speed = \frac{2(120) + 1260)}{60}\\\\speed = 25$

Thus speed of train is 25 meter per second

5 0

3 years ago

In the box, type in the number that will correctly complete the sentence.

Airida [17]

If she have 12 pencils and she gave 3/4 away then she will have 3 pencils left.

7 0

3 years ago

Read 2 more answers

Four balls of wool will make 8 knitted caps. How many balls of wool will Malcom need if he wants to make 6 caps.

julia-pushkina [17]

Answer:

He needs 3 balls of wool to make 6 caps

Step-by-step explanation:

Its simple you will understand if u dont ask me for a explanantion

8 0

3 years ago

What is the equation of the line perpendicular to 3x+y= -8that passes through -3,1? Write your answer in slope-intercept form. S

Gekata [30.6K]

Slope intercept form of a line perpendicular to 3x + y = -8, and passing through (-3,1) is $y=\frac{1}{3} x+2$

Solution:

Need to write equation of line perpendicular to 3x+y = -8 and passes through the point (-3,1).

Generic slope intercept form of a line is given by y = mx + c

where m = slope of the line.

Let's first find slope intercept form of 3x + y = -8

3x + y = -8

=> y = -3x - 8

On comparing above slope intercept form of given equation with generic slope intercept form y = mx + c , we can say that for line 3x + y = -8 , slope m = -3

And as the line passing through (-3,1) and is perpendicular to 3x + y = -8, product of slopes of two line will be -1 as lies are perpendicular.

Let required slope = x

$\begin{array}{l}{=x \times-3=-1} \\\\ {=>x=\frac{-1}{-3}=\frac{1}{3}}\end{array}$

So we need to find the equation of a line whose slope is $\frac{1}{3}$ and passing through (-3,1)

Equation of line passing through $(x_1 , y_1)$ and having lope of m is given by

$\left(y-y_{1}\right)=\mathrm{m}\left(x-x_{1}\right)$

$\text { In our case } x_{1}=-3 \text { and } y_{1}=1 \text { and } \mathrm{m}=\frac{1}{3}$

Substituting the values we get,

$\begin{array}{l}{(\mathrm{y}-1)=\frac{1}{3}(\mathrm{x}-(-3))} \\\\ {=>\mathrm{y}-1=\frac{1}{3} \mathrm{x}+1} \\\\ {=>\mathrm{y}=\frac{1}{3} \mathrm{x}+2}\end{array}$

Hence the required equation of line is found using slope intercept form

4 0

3 years ago