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liubo4ka [24]
3 years ago
11

Solve each system of equation using any method. 7 x + y = 5 2x - y = 4

Mathematics
1 answer:
nexus9112 [7]3 years ago
7 0

Answer:

x = 1

y= -2

Step-by-step explanation:

to solve this system of equation , simultaneously using the substitution method

we say let

7 x + y = 5 ............................................. equation 1

2x - y = 4 ................................................... equation 2

from equation 2

2x - y = 4 ................................................... equation 2

2x - 4 = y

y = 2x -4.......................................................... equation 3

put the value of the y = 2x -4 into equation 1

7 x + y = 5 ............................................. equation 1

7x + 2x - 4 = 5

9x-4 = 5

9x = 5 + 4

9x = 9

divide both sides by the coefficient of x which is 9

9x/9 = 9/9

x = 1

substitute the value of x = 1 into equation 3

y = 2x -4.......................................................... equation 3

y = 2(1) -4

y = 2 - 4

y = -2

to check if you are correct put the value of x and y into any of the equations and you will see that the left hand side will be equal to the right hand side.

2x - y = 4 ................................................... equation 2

2(1) -(-2) = 4

2 + 2 = 4

4=4................................... proved

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3 years ago
What is the square root of 100 times two divided by two
gogolik [260]

Answer:

10 is your answer

Step-by-step explanation:

√((100 * 2)/2)

Simplify. First, follow the Parenthesis. Combine 100 with 2

100 * 2 = 200

Next, divide by 2

200/2 = 100

Root 100

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10 is your answer

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An easier way to solving this is to first cancel out the 2's ( multiplying 2 and dividing 2 would do nothing), and just square rooting 100, giving you the answer 10.

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8 0
3 years ago
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Answer:

4/3*100^3*π

Step-by-step explanation:

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5 0
3 years ago
Ralph buys a desk that regularly sells for $250 and a desk chair that regularly sells for $145. both items are on sale at 15% of
Lunna [17]
C) (0.85 + x/100)(250+145) does not give the correct answer.

Explanation
A) works; adding the two costs together is 250+145=395.  We multiply this by 0.85 because 100%-15%=85%=0.85.  We also have x% tax, which is represented by x/100, added to 100% of the value, or 1.00.  Altogether this gives us 
395(0.85)(1+x/100) = 395(0.85 + (0.85x/100)) = 395(0.85) + 395(0.85x/100)
= 395(0.85) + 395(0.0085x)
B) works; we have 250+145 for the original price; we have 85% = 0.85 of the value; we also have 100% + x%, which is (100+x)/100.
C) does not work; (0.85+x/100)(395) does not take into consideration that you are finding the tax after taking the 85%.  This will simplify out to
0.85*395 + (x/100)(395) = 335.75 + 395x/100 = 335.75 + 3.95x, which is too much.
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6 0
3 years ago
Good morning temperature is -15° but the afternoon the temperature raises by 20° right in addition expressions for the afternoon
stealth61 [152]

Answer:

+ 5°

Step-by-step explanation:

Given,

Good morning temperature = -15°

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Hence, temperature in after noon is equal to + 5°.

7 0
2 years ago
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