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mixer [17]
3 years ago
11

Solve the simultaneous equations. to. 3 significant figures.3x^2 + y^2 = 202x + y =3​

Mathematics
1 answer:
sweet-ann [11.9K]3 years ago
5 0

Answer:

check explanation

Step-by-step explanation:

in eqn 2,

y = 3 - 2x

substitute for it in eqn 1

3x² + y² = 20

3x² + (3 - 2x)² = 20

3x² + 9 - 12x + 4x² = 20

Group like terms;

3x² + 4x² - 12x = 20 -9

7x² - 12x = 11

x(7x - 12) = 11

x = 11,

OR

7x - 12 = 11

7x = 11 + 12

7x = 23

x = 23/7

x = 3.286

To get y, substitute for x in eqn 2

WHEN x = 11,

y = 3 - 2(11)

y = 3 - 22

y = -19

WHEN x = 3.286

y = 3 - 2(3.386)

y = -3.772

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DochEvi [55]

Answer:

$149.50

Step-by-step explanation:

M varies directly as D

M ~ D

M = KD

Where:

M = money earn

D = Driveway

K = assumed constant

Therefore

M = KD

$80.50 = k * 7

K = $80.50 / 7

K = $ 11.50

To know how much he earns if he shoves 13 drive way, we repeat the relationship.

That is:

M = KD

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He makes $149.50 after shoving 13 driveways

3 0
3 years ago
A restaurant check is $34.59. how much will a 15% tip be
kobusy [5.1K]

Answer:

5.19

Step-by-step explanation:

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3 0
3 years ago
Read 2 more answers
Solve each system by substitution -7x+2y=18, 6x+6y=0
abruzzese [7]
The following pictures should explain well enough how to solve this would take to long to write out the end answer however are x=-12.5 and y=34.75 the steps are the following pictures Hope this helps!=)

8 0
3 years ago
You run at a pace of 8.5 minutes per mile in a 26.2 mile marathon. How many minutes will it take finish?
algol [13]
8.5 minutes per mile is equivalent to 

17 minutes
----------------
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and the reciprocal of that is


2 miles
-----------
17 min

Now multiply 26.2 miles by 

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------------ ,    obtaining         ---------------------------
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This simplifies to (17)(26.2)/2 minutes = 222.7 minutes, 

or

222.7 minutes        1 hr
-------------------- * ------------ = 3.7 hours
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4 0
3 years ago
2-5 please help! Please explain how you got the answers too! I more want to understand the math than get the answer
Andre45 [30]
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4 years ago
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