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2 years ago

Anyone know how to do the elimination method? pls help asap

Mathematics

2 answers:

givi [52]2 years ago

6 0

Hey there!

Check out image!

Answer is (-7,5)

dybincka [34]2 years ago

3 0

Answer:

(-7 , 5)

Step-by-step explanation:

For elimination method, you are "eliminating" one of the variables. This is achieved by relegating factors or multiples away so that both given expressions share the same term, which can be "eliminated".

In this case, you have the shared term of 7y. Isolate the term. Note the equal sign, what you do to one side, you do to the other.

For the first equation, Subtract 3x from both sides of the equation:

3x + 7y = 14

3x (-3x) + 7y = 14 (-3x)

7y = -3x + 14

For the second equation, subtract 2x from both sides of the equation:

2x + 7y = 21

2x (-2x) + 7y = 21 (-2x)

7y = -2x + 21

Note that both of them now share the same result, that being 7y. Using the equivalent system of equations (or expressions), you can solve them.

-3x + 14 = 7y

-2x + 21 = 7y

∴ -3x + 14 = -2x + 21

Isolate the variable, x. Note the equal sign, what you do to one side, you do to the other. Add 2x and subtract 14 from both sides of the equation:

-3x (+2x) + 14 (-14) = -2x (+2x) + 21 (-14)

-3x + 2x = 21 - 14

-x = 7

(-x)/-1 = (7)/-1

x = -7

Next, plug in -7 as x for one of the given equations to solve for y:

2x + 7y = 21

2(-7) + 7y = 21

First, simply by multiplying 2 with -7:

(2 * -7) + 7y = 21

(-14) + 7y = 21

7y - 14 = 21

Note the equal sign, what you do to one side, you do to the other. Do the opposite of PEMDAS. PEMDAS is the order of operations, and stands for:

Parenthesis

Exponents (& Roots)

Multiplication

Division

Addition

Subtraction

First, add 14 to both sides of the equation:

7y - 14 (+14) = 21 (+14)

7y = 21 + 14

7y = 35

Next, divide 7 from both sides of the equation:

(7y)/7 = (35)/7

y = 35/7 = 5

y = 5

Therefore, (-7 , 5) is your answer.

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Jaxon has $65 in his savings account. He deposits $15 every week. His father also deposits $25 into the account every time Jaxon

Grace [21]

Part A:
A coefficient can be either '15' or '25'.
A variable can be either 'w' or 'm'.
A constant is 65.

Part B:
Simply substitute, or plug-in, the numbers and solve.
***Step 1:
65+15w+25m --> 65+15(20)+25(3)
You do this because you are substituting the 'w' for the number
of weeks that Jaxon saved up for, which is 20, and the 'm' for the number
of times that Jaxon mowed the lawn, which is 3.
***Step 2:
65+15(20)+25(3) --> 65+300+75
Begin to solve, using PEMDAS, or whichever acronym you learned.
Remember, if you are using PEMDAS, recall that the order is Parenthesis,
Exponents, Multiplication/Division (whichever comes first), and
Addition/Subtraction (whichever comes first). Here, I checked for parenthesis.
I did find parenthesis, however, they do not have any expressions inside of
them, meaning that these parenthesis are for multiplying, and not for stating
order. So, you skip parenthesis. Next, you check for exponents, which you
find none of, so you skip over that. Now, we get to multiplying/dividing, so
you multiply the 15 and the 20 to get 300, and the 25 and 3 to get 75.
***Step 3:
65+300+75 --> 440
Now, we get to addition. You simply add everything up to get your final
answer: $440.

Part C:
If Jaxon had $75, then yes, the coefficients would change.
By subtracting $65 from $75, we can see that the total amount of money
from Jaxon's deposits and his lawn-mowing money is $10. Jaxon already
deposits $15 a week, meaning that, while using the current equation, Jaxon
CANNOT have $75 in his bank account. We can change the equation
so that Jaxon is able to have $75 in his savings account. You can change
the coefficient of 15 to 10, and the other coefficient of 25 to 0.
Now Jaxon is able to have $75 in his savings account.

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A man is 32 years older than his daughter and the product of their ages is 320..

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3 years ago

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A compact disc player costs £50 plus 17 1/2% Vat. Calculate the total cost of the compact disc player

Shtirlitz [24]

With Calculator:
To work out the multiplier, take the percentage, divide by 100 and add 1
17.5% / 100 = 0.175
1 + 0.175 = 1.175
£50 x 1.175 = £58.75

Without Calculator:
First work out easy percentages of 50 (if needed use previous answers (such as 10) to work out smaller percentages (such as 5%))
100% = 50
10% = 5
5% = 2.5
2.5% = 1.25
10% + 5% + 2.5% = 17.5%
5 + 2.5 + 1.25 = £8.75
Add this on to the original price:
£50 + £8.75 = £58.75

The total price, including VAT, is £58.75

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3 years ago

What is the area of the trapezoid?

ExtremeBDS [4]

<h2>Answer:</h2>

42 square units

<h2>Step-by-step explanation:</h2>

For a better understanding, I add an EFGH Rectangle.

The area of EFGH Rectangle = p x l

The area of EFGH Rectangle = 10 x 8

The area of EFGH Rectangle = 80cm²

The area of BHA Triangle = 1/2 x a x t

The area of BHA Triangle = 1/2 x 6 x 4

The area of BHA Triangle = 2 x 6

The area of BHA Triangle = 12cm²

The area of AGD Triangle = 1/2 x a x t

The area of AGD Triangle = 1/2 x 4 x 2

The area of AGD Triangle = 4cm²

The area of CFD Triangle = 1/2 x a x t

The area of CFD Triangle = 1/2 x 2 x 6

The area of CFD Triangle = 6cm²

The area of BEC Triangle = 1/2 x a x t

The area of BEC Triangle = 1/2 x 8 x 4

The area of BEC Triangle = 4 x 4

The area of BEC Triangle = 16cm²

The area of the trapezoid = EFGH Rectangle - (BHA Triangle + AGD Triangle + CFD Triangle + BEC Triangle)

The area of the trapezoid = 80 - (12 + 4 + 6 + 16)

The area of the trapezoid = 80 - 38

The area of the trapezoid = 42cm²

<h3>Conclusion :</h3>

The area of the trapezoid is <u>42 square units</u>

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2 years ago