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Solve the system using the addition method. Write your answer as an ordered pair. If there is no solution, write NS for your answer.9x + 7y = 381 4x - 7y = 14

Solve the system using the addition method. Write your answer as an ordered pair. If-example-1
User P C
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1 Answer

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The solution (x, y) is (4, 2/7)

Step-by-step explanation:

Addition method is the same as elimination method

9x + 7y = 38 ...(1)

4x - 7y = 14 ...(2)

Using addition method:

Let's eliminate y. To do this we need to ensure the coefficient of y in both equations are the same. wehave 7 in both but the signs are different.

Since they have different sign, we'll add equation 1 and 2:

9x + 4x + 7y + (-7y) = 38 + 14

13x + 7y - 7y = 52

13x = 52

divide both sides by 13:

13x/13 = 52/13

x = 4

substitute for x in equation 2:

4(4) - 7y = 14

16 - 7y = 14

16 - 14 = 7y

2 = 7y

y = 2/7

The solution (x, y) is (4, 2/7)

To check:

using (1): 9x + 7y = 38

9(4) + 7(2/7) = 38

36 + 2 = 38

User Mdarefull
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