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skelet666 [1.2K]
3 years ago
15

Solve the system of equations by substitution.

Mathematics
1 answer:
mojhsa [17]3 years ago
6 0

Answer:

6 = −4x + y

−5x − y = 21  

Answer:  (-3, -6)


2x + y = 20 6x – 5y = 12  

Answer:

(7 , 6)


Step-by-step explanation:

Solve the system of equations by substitution.

6 = −4x + y --> y = 4x + 6

−5x − y = 21

Substitute y = 4x + 6 into −5x − y = 21

−5x − (4x + 6) = 21

-5x - 4x - 6 = 21

-9x = 27

  x = - 3

y = 4(-3) + 6

y = -12 + 6

y = -6

(-3, -6)


Solve the system by the elimination method.

2x + y = 20

multiply the equation by (-3) ; 2x + y = 20  so

-6x - 3y = - 60

6x – 5y = 12

------------------add

-8y = - 48

  y = 6

2x + y = 20

2x + 6 = 20

2x = 14

 x = 7

(7 , 6)

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X^2 + 2x -4= 0

You need to remember one standard result

ax^2 + bx + c= 0

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By Comparing the coefficients,

a= 1, b=2, c=-4

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4 0
3 years ago
You invest 600 in a savings account which pays 1.7% interest annually. how much money will be in your account after 10 years if
tia_tia [17]
Lets get started :)

This is an example of a simple interest

The formula to calculate simple interest is:
I = prt  ( In the picture attached you can see what each stands for )

Given are initial amount → $600
                 interest anually → 1.7%
                 time  → 10 years

Let us convert the interest percentage into decimals
\frac{1.7}{100} = 0.017

I = ( 600 )( 0.017 )( 10 )
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7 0
3 years ago
Simplify this expression.<br> 6x + 3 – 4x + 2y + 7
SVEN [57.7K]

Answer:

2x + 10 + 2y

Step-by-step explanation:

6x + 3 – 4x + 2y + 7

(6x - 4x) = 2x

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4 0
3 years ago
14/15 + 8/15 + 4/5 please help
Annette [7]

Answer:

2.267

Step-by-step explanation:

Step 1 of 3: Add.

Add

Highlighted:14 over 15

14

15

Highlighted:+ Highlighted:8 over 15

8

15

+ 4 over 5

4

5

= Highlighted:22 over 15

22

15

+ 4 over 5

4

5

Step 1 of 3: Add, sub-step a: Add.

Add

14 over 15

14

15

+ 8 over 15

8

15

= ( 14 + 8 ) over 15

14 + 8

15

= 22 over 15

22

15

Step 1 of 3: Add.Hide

Step 2 of 3: Add.

Add

22 over 15

22

15

+ 4 over 5

4

5

= 34 over 15

34

15

Step 2 of 3: Add, sub-step a: Find common denominator.

Find common denominator

22 over 15

22

15

+ 4 over 5

4

5

= ( 22 × 1 ) over ( 15 × 1 )

22 × 1

15 × 1

+ ( 4 × 3 ) over ( 5 × 3 )

4 × 3

5 × 3

= 22 over 15

22

15

+ 12 over 15

12

15

15 is the least common multiple of denominators 15 and 5. Use it to convert to equivalent fractions with this common denominator.

Step 2 of 3: Add, sub-step b: Add.

Add

22 over 15

22

15

+ 12 over 15

12

15

= ( 22 + 12 ) over 15

22 + 12

15

= 34 over 15

34

15

Step 2 of 3: Add.Hide

Step 3 of 3: Simplify.

Simplify

34 over 15

34

15

= 2 and 4 over 152

4

15

Step 3 of 3: Simplify, sub-step a: Reduce fraction to lowest terms.

Reduce fraction to lowest terms

1 is the greatest common divisor of 34 and 15. The result can't be further reduced.

Step 3 of 3: Simplify, sub-step b: Convert improper fraction to mixed number.

Convert improper fraction to mixed number

34 over 15

34

15

= 2 and 4 over 152

4

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34 ÷ 15 = 2 remainder 4

3 0
3 years ago
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