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Likurg_2 [28]
3 years ago
15

Solve systems of equations by algebraically x-2y=7 2x+5y =5

Mathematics
2 answers:
Natali [406]3 years ago
8 0

Answer:

(5,-1) or x=5 y=-1

Step-by-step explanation:

I used the substitution method to solve this!

<em>1. Pick one of your equations and solve for one of the variables. I chose the first equation and solved for x.</em>

x-2y=7

(Move the -2y to the other side of the equation in order to get the x by itself. You do the opposite, so it becomes +2y.)

x=2y+7

<em>2. Now take your second equation and plug in what you got for x into the x variable.</em>

2(2y+7)+5y=5

(Multiple 2 by everything inside of the parentheses.)

4y+14+5y=5

(We want to get the y by itself, so move the 14 to the other side.)

4y+5y=-14+5

(Combine all the like terms.)

9y=-9

(Divide the 9 from the y. What you do to one side you must do to the other.)

y=-1

<em>3. Since you have one variable solved for. Now take the first equation and plug in your y.</em>

x-2(-1)=7

(Multiple -2 by -1)

x+2=7

(Move the 2 to the other side in order to get the x by itself.)

x=5

<em>4. If needed, plug in your x and y values into the equations in order to check your answer.</em>

Hope this could help!

kompoz [17]3 years ago
4 0
5,-1 because of the substitution method
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miss Akunina [59]

Answer:

381.18 cubic units

Step-by-step explanation:

Graph the region:

desmos.com/calculator/iwvreqjz2m

The region is a trapezoid.  When we rotate it about x = 1, we get a hollow cylinder shape.  We can either use washer method or shell method to find the volume.

If we find the volume using washer method, we'll have to use two integrals, one for the triangular part of the trapezoid and one for rectangular part.  If we use shell method, we only need one integral.  So let's use shell method.

Cut a thin, vertical slice of the region.  The width of this slice is dx.  The height of the slice is y₂ − y₁ = x − 0 = x.  The radius of the shell is x − 1.

The volume of the shell is:

dV = 2π (x − 1) (x) dx

dV = 2π (x² − x) dx

The total volume is the sum of all the shells from x=5 to x=7.

V = ∫ dV

V = ∫₅⁷ 2π (x² − x) dx

V = 2π ∫₅⁷ (x² − x) dx

V = 2π (⅓ x³ − ½ x² + C) |₅⁷

V = 2π [(⅓ 7³ − ½ 7² + C) − (⅓ 5³ − ½ 5² + C)]

V = 2π [⅓ 7³ − ½ 7² − ⅓ 5³ + ½ 5²]

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The volume is approximately 381.18 cubic units.

6 0
3 years ago
First come first served brainiest:)
adoni [48]

Answer:

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Step-by-step explanation:

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3 years ago
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jek_recluse [69]
Short Answer: Combine like terms
Remark

Just from what I see here, remove the brackets first and combine like terms second.

Discussion
8 - 2x + 4     The like therms are 8 and 4 First step
12 - 2x          That's the answer. Don't go any further. 2nd and last step



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Answer:

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Step-by-step explanation:

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