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2 years ago

Solve the system of equations: X+y+z=5 -3x-4y+4z=15 2x-y-4z=-8

Mathematics

1 answer:

atroni [7]2 years ago

6 0

Answer:

(x, y, z) = (3, -2, 4)

Step-by-step explanation:

The attachment shows a solution using a graphing calculator where the first equation is solved for z, and that expression is substituted into each of the other two equations. The solution to that system is (x, y) = (3, -2). Using these values in the expression for z, we find ...

z = 5 -(3 +(-2)) = 4

The solution is (x, y, z) = (3, -2, 4).

Your graphing calculator and/or online tools can give you the reduced row echelon form of the augmented matrix representing the system:

$\left[\begin{array}{ccc|c}1&1&1&5\\-3&-4&4&15\\2&-1&-4&-8\end{array}\right]$

If you're solving by hand, you can do the substitution described above to eliminate z from one equation. You can eliminate z from another equation by adding the last two:

-3x -4y +4(5 -x -y) = 15 ⇒ -7x -8y = -5

(-3x -4y +4z) +(2x -y -4z) = (15) +(-8) ⇒ -x -5y = 7

This pair of equations can be solved for x and y in any of the usual ways. Using the second equation to substitute for x, for example, gives you ...

-7(-5y -7) -8y = -5 ⇒ 27y = -54 ⇒ y = -2

x = -5(-2) -7 = 3

z = 5 -(3) -(-2) = 4

_____

<em>Additional comment</em>

If all that is needed is a solution, we prefer a graphical or matrix approach. These take about the same amount of time. Both require a little additional effort to determine exact values when the solutions are not integers.

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Please help me <br> Show your work <br> 10 points

Svet_ta [14]

<h2>Answer</h2>

After the dilation $\frac{5}{3}$ around the center of dilation (2, -2), our triangle will have coordinates:

$R'=(2,3)$

$S'=(2,-2)$

$T'=(-3,-2)$

<h2>Explanation</h2>

First, we are going to translate the center of dilation to the origin. Since the center of dilation is (2, -2) we need to move two units to the left (-2) and two units up (2) to get to the origin. Therefore, our first partial rule will be:

$(x,y)$ → $(x-2, y+2)$

Next, we are going to perform our dilation, so we are going to multiply our resulting point by the dilation factor $\frac{5}{3}$ . Therefore our second partial rule will be:

$(x,y)$ → $\frac{5}{3} (x-2,y+2)$

$(x,y)$ → $(\frac{5}{3} x-\frac{10}{3} ,\frac{5}{3} y+\frac{10}{3} )$

Now, the only thing left to create our actual rule is going back from the origin to the original center of dilation, so we need to move two units to the right (2) and two units down (-2)

$(x,y)$ → $(\frac{5}{3} x-\frac{10}{3}+2,\frac{5}{3} y+\frac{10}{3}-2)$

$(x,y)$ → $(\frac{5}{3} x-\frac{4}{3} ,\frac{5}{3}y+ \frac{4}{3})$

Now that we have our rule, we just need to apply it to each point of our triangle to perform the required dilation:

$R=(2,1)$

$R'=(\frac{5}{3} x-\frac{4}{3} ,\frac{5}{3}y+ \frac{4}{3})$

$R'=(\frac{5}{3} (2)-\frac{4}{3} ,\frac{5}{3}(1)+ \frac{4}{3})$

$R'=(\frac{10}{3} -\frac{4}{3} ,\frac{5}{3}+ \frac{4}{3})$

$R'=(2,3)$

$S=(2,-2)$

$S'=(\frac{5}{3} (2)-\frac{4}{3} ,\frac{5}{3}(-2)+ \frac{4}{3})$

$S'=(\frac{10}{3} -\frac{4}{3} ,-\frac{10}{3}+ \frac{4}{3})$

$S'=(2,-2)$

$T=(-1,-2)$

$T'=(\frac{5}{3} (-1)-\frac{4}{3} ,\frac{5}{3}(-2)+ \frac{4}{3})$

$T'=(-\frac{5}{3} -\frac{4}{3} ,-\frac{10}{3}+ \frac{4}{3})$

$T'=(-3,-2)$

Now we can finally draw our triangle:

8 0

3 years ago

Is this expression equivalent?<br> 3v+v and 12v over 3

xeze [42]

Yes this is equal because 3v+v is 4v and if you divide 12v by 3 you also get 4v

7 0

4 years ago

Read 2 more answers

A total of 1,650 boxes of Girl Scout cookies were sold last week. Each large box cost $3.50 and each small box cost $2.00. The G

s344n2d4d5 [400]

Answer:

900 large boxes were sold, and 750 small boxes.

Step-by-step explanation:

This question can be solved by a system of equations.

I am going to say that:

x is the number of large boxes of cookies sold.

y is the number of small boxes of cookies sold.

A total of 1,650 boxes of Girl Scout cookies were sold last week.

This means that

$x + y = 1650$

$x = 1650 - y$

Each large box cost $3.50 and each small box cost $2.00. The Girl Scout group earned $4,650.

This means that

$3.5x + 2y = 4650$

Since $x = 1650 - y$

$3.5(1650 - y) + 2y = 4650$

$5775 - 3.5y + 2y = 4650$

$1.5y = 1125$

$y = \frac{1125}{1.5}$

$y = 750$

$x = 1650 - y = 1650 - 750 = 900$

900 large boxes were sold, and 750 small boxes.

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3 years ago

Priya is hosting a poetry club meeting this week and plans to have fruit punch and cheese for the meeting. She is preparing 8 ou

Korvikt [17]

Answer:

i) Number of people in club = 12

ii) 96 ounces of fruit punch for 12people

iii) 24 ounces of cheese for 12 people

iv) Priya's budget for poetry club meeting in dollars = $7.87

Step-by-step explanation:

We are not given the options for the equations that could represent the quantities and constraints in this situation. We can tell we are to represent the information given above.

Number of people in the club = 12

8 ounces of fruit punch per person

For 12 people = 12×8 = 96 ounces of fruit punch

2 ounces of cheese per person

For 12 people = 12×2 = 24 ounces of cheese

A package of cheese = 16 ounces

The costs for 1package = $3.99

The costs for 16 ounces of cheese = $3.99

The cost for 24 ounces of cheese = (24×3.99)/16 = 5.985

The cost for 24 ounces of cheese = $5.99

One-gallon jug of fruit punch = 128 ounces

The cost of One-gallon jug of fruit punch = $2.50

The costs of 128 ounces of fruit punch = $2.50

The costs for 96 ounces of fruit punch = (96×2.5)/128 = 1.875

The costs for 96 ounces of fruit punch = $1.88

Priya's budget for poetry club meeting in dollars = $5.99 + $1.88 = $7.87

Cost per item for x number of people:

y = x(2.5/128) + x (3.99/16)

y = x(0.0195) + x(0.2494)

Cost equation for Priya's budget:

y = 96x(2.5/128) + 24x (3.99/16)

y = 96x(0.0195) + 24x(0.2494)

Since the total number of people to attend the meeting is 12, the constraint = 0≤x≤12

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3 years ago

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The answer is B and I am happy to help you out

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