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How do you do this equation?

solve simultaneous equations by substitution
2x + 3y = 7
2x + 7y = 19

1 Answer

8 votes

Answer:

(- 1, 3 )

Explanation:

Given the 2 equations

2x + 3y = 7 → (1)

2x + 7y = 19 → (2)

In (1) subtract 3y from both sides

2x = 7 - 3y → substitute into (2)

7 - 3y + 7y = 19

7 + 4y = 19 ( subtract 7 from both sides )

4y = 12 ( divide both sides by 4 )

y = 3

Substitute y = 3 into either of the 2 equations and solve for x

Substituting into (1)

2x + 3(3) = 7

2x + 9 = 7 ( subtract 9 from both sides )

2x = - 2 ( divide both sides by 2 )

x = - 1

solution is (- 1, 3 )

User Mark McKelvy
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