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s2008m [1.1K]
3 years ago
13

#18 please help me solve this

Mathematics
1 answer:
Alex777 [14]3 years ago
5 0

Answer:

x = -1

y = 1

Step-by-step explanation:

The system of equation is:

-7x + 2y = 9 ⇒ (1)

-4x - 7y = -3 ⇒ (2)

To solve the system multiply equation (1) by 7 and equation (2) by 2 to make the coefficients of y equal in values and different in signs, then add the two resulting equations to eliminate y and solve the new equation for x to find its value

∵ 7(-7x) + 7(2y) = 7(9)

∴ -49x + 14y = 63 ⇒ (3)

∵ 2(-4x) - 2(7y) = 2(-3)

∴ -8x - 14y = -6 ⇒ (4)

- Add equations (3) and (4)

∴ -57x = 57

- divide both sides by -57

∴ x = -1

Substitute the value of x in equation (1) or (2) to find y

∵ -7(-1) + 2y = 9

∴ 7 + 2y = 9

- Subtract 7 from both sides

∴ 2y = 2

- Divide both sides by 2

∴ y = 1

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A number doubled and has four added to it. The result is divided by three and then added to the product of the original number a
IrinaK [193]
X= a number

(2x+4)/3 + (x+2)= 20
Multiply everything by 3 to eliminate the fraction
(3/1)((2x+4)/3) + (3)(x+2)= (3)(20)
2x+4+3x+6= 60
5x+10=60
Subtract 10 from both sides
5x=50
divide both sides by 5
x=10

Check:
Substitute answer in original equation
(2x+4)/3 + (x+2)= 20
(2(10)+4)/3+(10+2)= 20
(20+4)/3+12= 20
24/3+12= 20
8+12= 20
20=20

Hope this helps! :)
8 0
4 years ago
What's 3.318 divided by 0.07? <br><br>THIS IS HOMEWORK AND IT'S DUE IN 2 DAYS
Bond [772]
The answer is ...............47.4
5 0
3 years ago
Read 2 more answers
No links, will be reported
kirza4 [7]

Answer:

(1,0)

Step-by-step explanation:

This is because a system of equations is when two lines cross to form a point that they share. (1,0) is the point where the two lines cross/intersect.

6 0
2 years ago
Read 2 more answers
Help PLEASE (look at picture)
elena-14-01-66 [18.8K]

Answer:

16

Step-by-step explanation:

So for QR is 1-(-3)=4

QT:|-2-2|=4

TS: |-2-(-2)|=4

RS: 2-(-2)=4

and they plus together is 4x

4x4 = 16

I hope this helps, have a blessed day. :D

6 0
2 years ago
Please help! I keep on getting the wrong answer!
valentina_108 [34]

Answer:

CODE: 1977.98

Step-by-step explanation:

A.

(To get the closest answer, round the circumference to the nearest ten thousandth.)

C = 2(3.14)r                      Circumference formula: C = 2πr

C = 2(3.14)(3)

C = 18.84

B.

A = (3.14)r²

A = (3.14)(3)²

A = (3.14)(9)

A ≈ 28.26

C. (It's asking for the circumference.)

C = 2(3.14)r

C = 2(3.14)(58)

C ≈ 364.24

D. (It's a linear pair, which is 180 degrees.)

4x + 2x = 180

6x = 180

x = 30

m∠ABD = 4x

m∠ABD = 4(30)

m∠ABD = 120°

E. (∠GHI & ∠JHK are vertical angles, so they are congruent.)

x + 7 = 3x - 21

28 = 2x

14 = x

F. (x = 14)

m∠JHK = 3x - 21

m∠JHK = 3(14) - 21

m∠JHK = 42 - 21

m∠JHK = 21°

G. (Supplementary - two angles that add up to 180 degrees.)

180 - 84

= 96°

CODE: E(C - D) - F(G - B) - A

CODE: 14(364.24 - 120) - 21(96 - 28.26) - 18.84

CODE: 14(244.24) - 21(67.74) - 18.84

CODE: 3419.36 - 1422.54 - 18.84

CODE: 1977.98

8 0
2 years ago
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